It is officially September, which means summery desserts on on their way out and fall desserts are on their way in. However, I couldn’t let summer end without attempting something a little crazy – turning one of my favorite summery desserts, Key Lime Pie, into a cake.
I know – it sounds odd. But I had a vision of a lightly lime scented vanilla cake, filled with a tangy lime curd, topped with some tasty buttercream to tie it all together. When it was all done, this cake was a slam freakin’ dunk.
Life has been an absolute whirlwind lately! First off, we closed on our new house, so we’re officially homeowners in Philadelphia! It’s been a barrage of moving boxes and trips to Home Depot all month, and there’s really no end in sight. People always told me that once you own a home, the improvement projects never stop. I totally get that now. Small updates have turned into full remodels, but we’re excited to transform the space into something we love.
Steve and I also took a trip up to Rhode Island about 2 weeks ago to celebrate my birthday (8/24 – hayyy to all my fellow Virgos). We spent the trip eating lobster, hanging out on Block Island, walking the cliffs of Newport, and the trip ended with quite the birthday surprise. We’re engaged!
Steve really had me going, thinking he set up a nice dinner for my birthday, when in fact, it was a super thoughtful proposal (to which I obviously said yes!). We ended up actually moving out of our old apartment just a day after getting back from our trip, so life is going a mile a minute (but all good things!).
Back to key lime pie cake
The components of this pie-turned-cake are as follows:
- The base is a vanilla cake with lime zest, which helps to marry the vanilla and lime curd flavors throughout.
- The filling is a fresh, homemade lime curd (which is much easier to make than you think it’s going to be)
- The frosting is a graham cracker buttercream. It starts as a simple vanilla buttercream, but part of the powdered sugar is replaced with finely crushed graham cracker crumbs that give this cake a “pie crust” element.
This cake takes a little patience to make, but it’s well worth the wait. The big key to making this cake work is to contain the lime curd in the center of the cake, which is easily done by piping a frosting barrier around the edge to prevent any ooze. Other than that, it’s pretty straightforward!
Looking for more lime desserts?
Luckily, it’s one of my favorite flavors! Check out some of my other lime desserts below.
Key Lime Pie Cake
- Mixing Bowls
- Stand Mixer
- Cake Pans
- 1 cup all purpose flour
- 1/3 cup sugar
- 1/2 tbsp baking powder
- 1/4 tsp salt
- 1/2 cup milk
- 1/4 cup canola oil
- 1 tsp vanilla extract
- 1 egg beaten
- zest of half a lime
- 6 tbsp fresh lime juice
- zest of one lime
- 4 egg yolks
- 5 tbsp butter
- 1/2 cup granulated sugar
- 6 tbsp unsalted butter softened to room temperature
- 1/2 cup graham cracker crumbs or 2.5 sheets, crushed finely
- 1.5 cups powdered sugar
- 1/2 tsp vanilla extract
- 1/2 tbsp milk may need to add more to reach desired consistency
- Preheat oven to 350F
- Combine flour, sugar, baking powder, salt in a medium bowl.
- In a separate bowl, beat together egg, canola, milk, vanilla, lime zest.
- Combine wet and dry ingredients into one bowl and stir until you have a uniform batter.
- Pour into a greased 8" or 9" cake pan and bake for 25-30 minutes, until a toothpick comes out clean.
- While the cake is baking, start on your lime curd.
- Stir egg yolks, sugar, lime juice, and lime zest in a small saucepan until well combined. Put over low heat and stir consistently with a wooden spoon until the mixture begins to thicken. Add butter and stir until smooth.
- Remove from heat and pour into jar and allow it to cool.
- Once cake is out of the oven (you can level off the top if you wish), place is on a cooling rack and allow it to come to room temp.
- While it’s cooling, make your frosting. Combine softened butter with powdered sugar and vanilla and beat in the bowl of a stand mixer until mixture is uniform. Add graham cracker crumbs and beat on medium speed. Once well incorporated, add milk a little at a time to thin the frosting out to the proper consistency.
- Once cake is cooled, pipe a ring of frosting around the outer edges to hold in the lime curd. Then fill your cake with curd and pop it in the fridge to set.
- Once the curd has firmed up a bit (give it 30 min or so), frost your cake as you normally would, slice it, and enjoy!