Ingredients: Unsweetened chocolate, Boiling water, Baking soda, Cake and pastry flour, Salt, Baking powder, Unsalted butter, at room, Granulated sugar, Eggs, separated, Pure vanilla extract, Sour cream, ICING:, Unsalted butter, Brown sugar, Milk, Icing sugar, sifted, Cocoa, GARNISH:, Strawberry jam or preserves, Toasted sesame seeds, ...