Preheat oven to 350 degrees F (175 degrees C). Grease a 9-inch heart-shaped pan with butter and dust with some extra bread crumbs.
Cream 1/2 cup plus 1 tablespoon butter in a bowl with an electric mixer; mix in 2/3 cup white sugar and vanilla sugar. Add eggs one at a time, beating well after each addition, until light and foamy.
Place 5 ounces 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. Cool for a few minutes, then blend into egg mixture. Mix almond meal with bread crumbs and fold into the chocolate batter. Pour batter into the prepared pan.
Bake in the preheated oven on the lowest rack for 45 minutes. Remove from oven and cook completely, about 1 hour. Remove from pan.
Place 5 ounces 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. Cool for a few minutes, then mix in confectioner's sugar.
Cream 1/2 cup plus 2 tablespoons butter in a bowl with an electric mixer until creamy. Stir in chocolate-sugar mixture and almond extract until ganache is smooth.
Cut heart cake horizontally into 2 layers. Cover the bottom layer with some chocolate ganache and place second layer on top. Cover heart on all sides with remaining chocolate ganache.
Roll out marzipan into a thin layer on parchment paper. Cut out circles with a small glass to make petals; you need about 12 petals per rose. Roll one of the circles into a spiral shape for the center of the rose. Add the next marzipan circle and roll it around the center piece. The marzipan should just stick together. If you need extra "glue", use some water. Decorate cake with pink roses and other candy to your liking.