Talking Heart Cake

Ingredients:

• 2 packages of 420-450 g dry vanilla sponge cake mix (+ all necessary additional ingredients)
• 1 tube (450 g) of white glaze
• 1 package (280 g) marshmallows
• 1/4 cup water
• 8 drops green liquid food coloring
• 2 packages of powdered sugar (450 g each)
• 4 tablespoons unsalted butter, room temperature
• Pink or red liquid food coloring, for writing

Preparation:

1. Preheat oven to 350°F (175°C). Spray a 9-inch round pan and a 9-inch square pan (2 inches deep) with cooking spray.
2. Mix the sponge cake dough according to package directions; divide the dough evenly among the pans. Bake until a toothpick inserted into the cake comes out clean, 30-35 minutes.
3. Let the cakes cool, then remove them from the pans. Trim the domed tops of the cakes with a long serrated knife to flatten them. Cut the round cake in half.
4. Working on a cake board (you can cut a heart out of it to fit the cake) or cutting board, place 2 half-moon sponges on either side of the square sponge to form a heart.
5. Cover the cake with white icing, filling all the spaces between the layers.
6. Combine the marshmallows and water in a large microwave-safe bowl. Microwave, stirring with a rubber spatula, until the marshmallows are melted and smooth, 1-2 minutes. Add green food coloring and stir until smooth.
7. Transfer the marshmallow mixture to the bowl of a stand mixer. Mix, gradually adding almost all of the powdered sugar, setting aside 0.5 cups, and beat until smooth. Stir in the butter.
8. Transfer the fondant to a sheet of parchment paper and knead, incorporating powdered sugar, until the mixture is no longer sticky. Dust the parchment paper with additional powdered sugar; roll the fondant into a sheet large enough to cover the cake, at least 32 x 40 cm.
9. Carefully invert the parchment paper and fondant onto the cake; remove the parchment paper. Gently press the fondant onto the sides of the cake and smooth it out with your hands; trim off any excess. Shake off any excess sugar.
10. Use the wide end of a chopstick to write on the fondant (it's best to do this before the fondant dries). Use a small brush to paint the letters with red or pink food coloring.