Yields: 8 servings
regular cake batter
1 egg yolk
4 tablespoons unsalted butter, softened to room temperature
4 tablespoons superfine sugar (or granulated sugar)
8 ounces mascarpone cheese, softened to room temperature
6 tablespoons powdered sugar
1 teaspoon pure vanilla extract
1/3 cup heavy whipping cream, cold
1 (7-ounce) package marzipan (store-bought), at room temperature
¼ teaspoon yellow food coloring powder (see tips)
1 cup candied pecans, store-bought
Making guava cake filling:
Trim, peel and chop the guavas. Place them in a saucepan and add 4 tablespoons of water. Bring to a boil, then immediately lower the heat to a gentle simmer for about 8 minutes. The mixture should be softened. Remove from the heat. Filter the mixture, using a large-mesh strainer and a spatula. Remove and discard the solids (guava seeds).
In a stainless-steel mixing bowl, using an electric handheld mixer, whisk the eggs with 4 tablespoons of superfine sugar until the texture thickens. Make a "double boiler" (a pot filled with hot water, covered with a piece of cloth) and place the bowl filled with whisked eggs on top). Slowly pour in the guava mixture so that the eggs don't curdle and continue whisking the eggs at full speed for about 3-4 minutes. Check the temperature of the eggs; they should feel warm to the touch. Remove from the double boiler, add the softened butter. Continue whisking at full speed for about 5 minutes. Strain the liquid through a fine mesh sieve into a bowl to remove any remaining solids. Let cool to room temperature, cover with plastic wrap and refrigerate for at least 30 minutes.
For the cake sheets:
Preheat the oven to 375°F.
Pour the cake batter into a 14-inch square cake pan (you could use any other shape you have available in your kitchen).
Bake the cake for 5 minutes at 375°F, then lower the temperature to 350°F and bake for another 40 minutes (Time will vary depending on the size of the pan).
Remove from the oven. Let cool completely.
Using a bread knife, slice the cake in half, horizontally.
For the cake topping:
Flatten the marzipan and color it with the coloring powder. Using disposable gloves, knead the marzipan until it changes color; it's okay if it's not fully incorporated.
Place the marzipan between 2 sheets of plastic wrap. Roll with a rolling pin to about a 1/8-inch thick layer.
Create a 14" by 14" square of marzipan.
For the cake frosting:
Whisk the mascarpone cheese to soften it until fluffy. Add 4 tablespoons of powdered sugar and the vanilla extract.
Whip the heavy cream (at a low speed) for 2-3 minutes until creamy and smooth. Add the rest of the powdered sugar. Gently fold in the whipped cream in stages.
Make sure the cake has cooled completely.
Place one sheet of cake onto a cake platter, leaving 2 rectangles of parchment paper beneath the cake (for easy release later).
Cover the cake with a thick layer of guava filling and smooth it out using a spreader; this will act as the glue for the second sheet of cake.
Add the other layer of cake. Top with the sheet of marzipan.
Cover the sides of the cake with the vanilla frosting, then add the candied pecans.