For the almond cake: Preheat the oven to 325 degrees F. Grease two 8-inch round cake pans with butter and line with parchment.
In a stand mixer fitted with the paddle attachment, cream the butter and sugar together until light and fluffy, 8 to 10 minutes. Add the egg yolks, one at a time, fully combining before each addition. Keep mixing until light and pale. Add the almond meal and mix to combine.
In another bowl, sift together the flour and baking powder to combine. Set aside.
Combine the evaporated milk and almond liqueur. Set aside.
With the mixer on low speed, alternate adding one-third of the flour mixture and one-half of the evaporated milk mixture to the creamed butter. Start and end with the flour, and do not overmix.
With a hand mixer or stand mixer, whisk the egg whites in a clean bowl until stiff. Gently fold into the batter.
Divide the batter between the prepared cake pans. Bake until the tops are golden and spring back when touched, 30 to 35 minutes.
Let cool for about 5 minutes, then run a paring knife or mini offset spatula around the pans and unmold the cakes onto a rack. Let cool completely, 15 to 20 minutes.
For the almond liqueur simple syrup: Whisk the water and sugar together in a small saucepan and bring to a boil over high heat. Boil for 2 to 3 minutes, then turn off the burner and let cool for about 20 minutes
Once cooled, stir in almond liqueur. Reserve.
For the key lime buttercream: In a stand mixer with the paddle attachment, cream the butter and cream cheese together until light and fluffy, about 5 minutes. Mix in the powdered sugar, one cup at a time, and then add the lime juice and zest. Scrape down the bowl and mix for another 5 minutes, until satiny and fluffy. Reserve.
For the raspberry compote: In a medium saucepan over medium heat, combine the raspberries, blackberries, sugar, water and lime juice. Cook until you can start to crush the berries with the back of a spoon, 5 to 10 minutes. Cook for another 5 minutes to thicken a bit. Remove from the heat and set aside.
To assemble: Slice each cake horizontally into two equal layers. Place the first layer, cut-side up, on a cake board. Using a pastry brush, brush the surface with about 3 tablespoons of the almond syrup.
Transfer the buttercream to a pastry bag fitted with a 1/4-inch round tip and pipe a border around the edge of the cake.
With a mini offset spatula, spread a thin layer of buttercream in the center of the cake layer. Then, staying inside the piped border, spread a thin layer of the raspberry compote on top of the buttercream.
Place another cake layer, cut-side up, on top. Repeat with the rest of the layers.
To decorate the top of the cake: Pipe a border of buttercream beads around the edge and then spread with a thin layer of buttercream. Top with blackberries, raspberries, and white chocolate decorations if using. Sprinkle with powdered sugar, and enjoy.
This recipe was created by a contestant during a cooking competition. It has not been tested for home use.