Preheat oven to 400 degrees F (200 degrees C). Line a rimmed baking sheet with parchment paper.
Beat egg whites in a glass, metal, or ceramic bowl with an electric mixer until stiff peaks form.
Combine egg yolks, 1 cup plus 2 tablespoons butter, and sugar in a large bowl; beat with an electric mixer until smooth and creamy.
Place 4 ounces milk chocolate in top of a double boiler over simmering water. Stir frequently, scraping down the sides with a rubber spatula to avoid scorching, until chocolate is melted, about 5 minutes. Remove from heat, add remaining 3 ounces milk chocolate and stir until chocolate is melted. Cool for 5 minutes.
Stir melted chocolate into the egg yolk mixture until well combined. Add almonds and flour and mix well. Fold beaten egg whites into batter. Pour batter onto the prepared baking sheet and spread out evenly.
Bake in the preheated oven until chocolate cake is set and a toothpick comes out clean, 8 to 10 minutes, depending on the thickness of the cake. Allow to cool completely, about 1 hour.
Line a baking sheet with parchment paper.
Cut cooled cake into small, 3/4-inch squares. Spread a thin layer of jam on half of the chocolate squares and place a second chocolate square on top to create little cubes.
Combine 7 ounces milk chocolate and dark chocolate in a bowl. Place 2/3 of the mixed chocolate in top of a double boiler over simmering water. Stir frequently, scraping down the sides with a rubber spatula to avoid scorching, until chocolate is melted, about 5 minutes. Remove from heat, add remaining chocolate mixture, and stir until chocolate is melted.
Pierce chocolate cubes with a fork and dip into chocolate so it is completely covered with chocolate. Use a spoon to remove excess chocolate and place on the prepared baking sheet to set. Allow to set at room temperature.