Butter and flour 2 (9 x 5 x 3-inch) loaf pans and set aside. Preheat the oven to 350 degrees.
With an electric mixer cream the butter with 1/4 cup of the sugar and beat until it looks light and fluffy. Add the almond paste a bit at a time and continue to beat until the mixture looks light and fluffy. Add the yolks, 1 at a time, beating well after each addition, then beat in the vanilla.
Beat the egg whites with a pinch of salt until soft peaks form. Add the remaining sugar, a tablespoonful at a time, until the egg whites are stiff but not dry. Fold one quarter of the beaten whites into the butter/almond paste mixture, then fold that lightened mixture back into the remaining egg whites, sprinkling and adding in flour as you fold. Add melted chocolate, cutting through the batter with rubber spatula to marble the batter. Pour the batter into the prepared loaf pans and bake for 1 hour and 15 minutes or until a cake tester comes out clean when inserted in the middle of the cake; the cakes should be golden brown and pull away from sides of the pan. Let them set in the loaf pans for 15 minutes. Run a sharp knife around the edges and loosen the cakes onto a rack to cool completely.
IDEAS TO DRESS UP POUND CAKE:
Take remaining almond paste from can, stir in the grated orange zest and some whipped cream or even sour cream to make the mixture looser; fold in remaining whipped cream and use as a topping with sliced and sugared strawberries or raspberries.
QUICK ICE BOX CAKE:
Layer some cake slices in the bottom of a loaf pan; sprinkle with liqueur and top with fruit and whipped cream. Repeat with another layer at least, ending with cake on top. Cover and refrigerate until cake is moistened.
QUICK CHOCOLATE GLAZE:
Combine cocoa, heavy cream, butter and sugar in a saucepan. Over low heat cook, stirring constantly, until smooth and thick, about 5 minutes. Remove from heat, add vanilla. Drizzle glaze over slices of almond cake topped with ice cream. Store remaining glaze in covered jar, in the refrigerator for several weeks; reheat to boiling before reusing.