1. Preheat oven to 350° F. Grease and flour a 9×9 inch baking pan; set aside. In a medium saucepan, stir together granulated sugar and water. Cook and stir over medium heat until the sugar dissolves and mixture almost boils. Remove from heat. Add chocolate; stir until melted (mixture may appear slightly grainy). Place egg product in a large bowl. Gradually stir the chocolate mixture into egg product; stir in vanilla (mixture may appear slightly grainy). Set aside.

2. In a small bowl, stir together the flour, cocoa powder, flax seeds, and baking powder. Add flour mixture to egg product mixture, whisking until smooth. In a medium bowl, beat egg whites with an electric mixer on medium speed until stiff peaks form (tips stand straight). Stir a small amount of the beaten egg whites into the chocolate mixture to lighten. Fold remaining egg whites into chocolate mixture. Spread in the prepared pan.

3. Bake for 30 minutes. Cool cake in pan on a wire rack for 10 minutes. Remove cake from pan. Cool completely on a wire rack.

4. Transfer cake to a cutting board. Using a 3¼ inch heart shaped cutter, cut 6 heart-shaped pieces from cake. Sprinkle tops with powdered sugar, if desired. Top with raspberries and mint leaves, if desired.