Best Ever Lemon KitKat Cake with Lemon White Chocolate Buttercream
Tender and fluffy lemon cake layers with lemon white chocolate buttercream and a lemon white chocolate wafer cookie crunch filling make up the most delicious Lemon KitKat Cake inspired by Lemon KitKat candy bars.
Lemon KitKats
During a recent visit to the grocery store, I found myself meandering down the candy aisle. Not something I usually do, but it’s nearly Easter, which means Easter candy! How could I resist?! I quickly locked eyes on a bright yellow bag of KitKats. Before you question my pick in candy, you must know – these weren’t just any KitKats. No, these were special. These were LEMON KitKats.
If you’re new here, I must inform you that my love of lemon desserts and treats has grown immensely over the years – thanks to my mom’s influence. (She loves all things lemon and makes the most delicious lemon bars – which inspired my Lemon Bar Cake). I used to pick chocolate without hesitation, but now, lemon flavored desserts have me thinking twice about my usual quick jump to chocolate or peanut butter (my other go-to). Sometimes the freshness and tartness of lemon really hits the spot.
And this cake does just that!
Lemon KitKat Cake
To recreate the Lemon KitKat candy bar in a cake, I made lemon cake layers, a lemon white chocolate buttercream, and a lemon white chocolate wafer cookie crunch filling.
The lemon cake is fluffy and moist, thanks to a combination of egg whites, lemon instant pudding mix, and a heaping one and a quarter cup buttermilk! I think the lemon instant pudding mix is a must, but if it’s something you can’t get your hands on, add an extra teaspoon of lemon emulsion and the zest of one lemon to the cake batter in place of it.
For the buttercream, we’re using my white chocolate buttercream and a bit of lemon emulsion (you can also use extract). This replicates the white chocolate coating on the outside of the KitKat bars and is an extremely delicious combination.
Wafer Cookie Crunch Filling
To mimic the crunch of the wafer from the KitKat bar, we’re taking some inspiration from Milk Bar and making a crunch filling. Christina Tosi, founder of Milk Bar, often takes elements like pretzels and potato chips, bakes them with butter, brown sugar, and milk powder, and then coats the clusters with white chocolate to give her cakes a layer of texture that doesn’t get soggy.
For the wafer cookie crunch, you’ll want to grab wafer cookies like Loacker lemon cream-filled wafer cookies. If you can’t find lemon flavored wafer cookies, you can absolutely use vanilla wafer cookies, like Voortman’s. With the vanilla wafer cookies, you’ll want to add the zest of a second lemon to the recipe below.
Once we bake the crushed wafer cookies with milk powder and butter, we get crunchy clusters that we’ll then coat with white chocolate. Once that white chocolate hardens, it ensures the clusters maintain their crunch.
One note about the filling – it’s highly munchable. Try to save a little for the cake 😉
How to Make a Moist Cake from Scratch
Don’t forget to follow my go-to tips for getting moist cakes that rise well:
- Preheat your oven for 30 minutes prior to baking.
- Use good quality pans like Fat Daddio.
- Spray your pans with nonstick spray and line with parchment paper.
- Make sure to beat the butter, sugar, oil and eggs really well. The mixture should be smooth in texture and nearly doubled in volume when you’re done mixing. THIS ONE IS IMPORTANT!
- Don’t overmix your cake batter once you add the dry ingredients.
- Use room temperature wet ingredients. Not cold at all.
- Use fresh baking powder.
- Bake until a toothpick inserted in the center of the cake comes out with a few moist crumbs on it. REMEMBER: the cake continues to bake for a few minutes while it cools in the pan.
Lemon KitKat Cake
Ingredients
FOR THE CAKE
- 3 cups (345 g) cake flour
- 2 teaspoons (8 g) baking powder
- 1/2 teaspoon (3 g) salt
- 3/4 cup (169.5 g) unsalted butter, at room temperature
- 1 3/4 cup (350 g) granulated sugar
- 1/4 cup (2 oz.) instant lemon pudding mix
- 6 large egg whites, at room temperature
- 1 1/4 cup (300 g) buttermilk, at room temperature
- 1 teaspoon (4.2 g) lemon extract
- Yellow food coloring optional
FOR THE WAFER COOKIE CRUNCH FILLING
- 1 1/2 cups (75 g) milk powder, divided
- 8.8 ounces (250 g) lemon wafer cookies, crushed but not finely ground
- zest of one lemon
- 1/2 cup (113 g) unsalted butter, melted
- 6 ounces white chocolate chips, melted
FOR THE LEMON WHITE CHOCOLATE BUTTERCREAM
- 6 ounces white chocolate chips
- 1/4 cup (60 g) heavy whipping cream
- 2 cups (452 g) unsalted butter, slightly cold
- 6 cups (750 g) powdered sugar, measured then sifted
- 2 teaspoons (8.4 g) lemon extract
- Pinch of salt
- Yellow food coloring, optional
Instructions
FOR THE CAKE
- Preheat your oven to 325 degrees F. Spray three 8-inch round cake pans with nonstick spray, line the bottoms with parchment paper, and spray again. Set aside.
- In another medium size bowl, whisk together the cake flour, baking powder, and salt. Set aside.
- In a bowl of a stand mixer fitted with a paddle attachment, beat the butter, sugar, and pudding mix together on medium-high speed, until light and fluffy, about 2 to 3 minutes.
- With the mixer on medium speed, add the egg whites, one at a time, making sure to scrape downt he sides and bottom of the bowl between additions. Stir in the lemon emulsion.
- Continue to beat on medium-high speed for about 2 minutes, until the mixture gets smooth in texture and slightly bigger in volume.
- With the mixer on low speed, alternately add the flour mixture and the buttermilk, starting and ending with the flour mixture. Mix until combined. Fold in food coloring, if using.
- Divide batter evenly among your pans, about 16 ounces of batter in each pan.
- Bake the cakes, about 20 to 25 minutes. Let cool on wire racks for 10 minutes before inverting them onto cooling racks to cool completely.
FOR THE WAFER COOKIE CRUNCH FILLING
- Preheat your oven to 275 degrees F. Line a baking sheet with parchment paper. Set aside.
- In a medium size mixing bowl, stir together 1 cup of the milk powder, the wafer cookies, and lemon zest.
- Pour in the melted butter and stir the mixture until the wafer cookies are "wet."
- Spread the cookie clusters on the baking sheet and bake for 15 minutes. Let cool completely.
- In a medium size mixing bowl, combine the baked cookie clusters and the additional ½ cup milk powder.
- Pour the white chocolate over the crumbs and toss until the clusters are covered. Spread the clusters are parchment to dry.
FOR THE BUTTERCREAM
- In a microwave safe bowl, combine the white chocolate and heavy cream. Heat in 30 second intervals, stirring between each, until the white chocolate is melted and the mixture is smooth. Set aside to cool.
- In the bowl of a stand mixer fitted with the paddle attachment, beat the butter on medium-high until light and fluffy, about 2 minutes.
- Gradually add the white chocolate ganache and mix until the mixture is smooth. Turn the mixer off and scrape down the sides and bottom of the bowl.
- With the mixer on low, gradually add the powdered sugar, followed by the lemon extract and salt. Mix until combined. Add yellow food coloring, if using. Mix until incorporated completely. Turn the mixer to medium-high and beat the frosting for an additional 3 to 5 minutes.
ASSEMBLY
- Spread a small dollop of frosting onto a cake board. Place the first cake layer, top side up, on the board.
- Evenly spread about 1 cup of buttercream over the cake. Cover with the wafer cookie crunch. Pat the clusters into place.
- Place a second cake layer on the filling and repeat step 2.
- Place the third cake layer, top side down, on top of the second layer of filling. Lightly coat the cake with a thin layer of buttercream to lock in the crumbs. Freeze the cake for about 10 to 15 minutes to set the frosting.
- Finish frosting and decorating the cake with the remaining buttercream. Top with more wafer cookie clusters.
Hi. Was reading recipe for Kit Kat lemon cake. You mention a shortbread crust layer that will come out attached to cake layer.
Where is that in ingredients and directions??
Thx
Typo! Let me fix that!
In the directions for this cake it says something about a shortbread crust, however I don’t see any directions for a shortbread crust. Am I totally missing something?
Nope. Missed cleaning that up when I was editing.
I decided to make this today! I couldn’t find lemon wafer cookies so I used vanilla and lemon zest. But when I was making the crumble, I forgot to add a second lemon to it. I figured I could just add another lemon zest to the white chocolate. Well, I learned something new today, lemon zest will cause white chocolate to seize up making it unusable. Crazy! I guess I’m headed back to the store to start over on the crumble. Can’t wait to eat this cake!
Looks delicious! How would you make this into a 9X13 cake?
About the same bake time
Where can I find the lemon cookies for this recipe? I’m anxious to try this. Thank you.
A regular grocery store or amazon?
Hi Courtney,
I am wondering about some of the ingredients…
What brand of lemon emulsion do you use?
What brand of milk powder do you use?
What brand/kind of white chocolate chips do you use?
And did you use yellow food coloring in the cake in the pictures and if so what kind?
Thanks:)
Way overthinking this one probably, but have a question. So if I’m using lemon Kit Kats then I obviously don’t need the other cookies correct? Also, do you know how many kit lat’s I would need for this? So where it calls for the cookie mixture I would use the kit Kat’s?
Yes you would use them where it calls for the cookies.
What is baking time for 9×13?
About the same, keep your eye on it.
I’m also wondering about the milk powder you are referring to. Could you please recommend a brand or type.
Thank you.
Just any type you can get at the store.
Can’t wait to bake this cake!
What kind of scraper did you use to make the stripes on your cake? It’s so pretty and classy!
Its from my set! https://shop.cakebycourtney.com/collections/shop-all/products/cake-scraper
So on the recipe for the cake it lists lemon extract but in the written out direction it says lemon emulsion. So I did one in one half tsp. Lemon emulsion and one half tsp. Lemon extract
In your tips section, it says to beat the sugar, butter, oil and eggs. See no mention of oil in the recipe.
It doesn’t say oil. It says beat the butter, sugar, and pudding mix together.
It does say oil. I was wondering and came to ask about the same thing. Be fore the recipe it says. “Make sure to beat the butter, sugar, oil and eggs really well.”
I love the lemon KitKats so I am very excited to make this.
Hello, what if I accidentally put the whole 3.4oz pack of instant pudding in the mix. I didn’t read the 1/4 cup?! 😳😦
You’ll be ok. Extra lemon flavor… and I wouldn’t be mad about that 🙂
We loved this cake and are now addicted to Lemon Cream Kit Kats. Unfortunately they’re only around during the Spring/Easter so sad.
We made a few adjustments as I couldn’t find lemon wafer cookies so used Vanilla Vortmans. After adding 2 t lemon zest, we didn’t notice enough lemon flavor so we added a tiny bit of lemon baking oil to the white chocolate. We also used lemon oil instead of extract/emulsion. Love that stuff!! I also chose to make a white chocolate Swiss meringue as I find American buttercreams too sweet. With those few substitutions, it was an awesome cake! Thanks for sharing! For Mother’s Day I’m going to use my lime baking oil and try with this recipe.
Hi,
My husband is obsessed with lemon kit kats. If I used the actual kit kats should I leave out the white chocolate? Would malted milk powder work?
Thank you!
The white chocolate helps bind all the filling elements together. I’d either make the filling as is, or just use chopped lemon kit kats.
Hello! This looks amazing! How would you add the filling if you were making this into a sheet cake? Do I need to make two layers?
Yes I would make two and stack with the filling in between.
Could I make this recipe without the instant pudding? I know the lemon flavor will not be as strong, but will it affect the texture?
Not really, maybe just add a couple extra tablespoons sugar in place of it.
Is lemon emulsion and lemon extract the same thing?
No. One is alcohol based and one is water based.
What changes need to be made to make this on a baking sheet pan?
Can’t wait to make this!
Not much actually – I actually share this cake as a sheet cake here: https://studio5.ksl.com/lemon-kitkat-cake-wafer-cookie-crunch-filling/
what’s baking time and temp for cupcakes?