For syrup, in a small saucepan melt the 2 tablespoons margarine or butter. Stir in the brown sugar and half-and-half or light cream. Cook and stir just until blended. Pour syrup into an 8x4x2-inch loaf pan or divide between two 10-ounce custard cups. Sprinkle almonds or pecans evenly over the syrup. Set pan or custard cups aside.
For batter, in a medium mixing bowl stir together the flour, granulated sugar, cocoa powder, baking powder, and baking soda. Add milk, 2 tablespoons margarine or butter, egg or egg white, and vanilla. Beat with an electric mixer on low to medium speed about 30 seconds or until combined. Beat on medium to high speed for 1 minute. Gently pour or spoon the batter over the syrup and nuts in the pan or custard cups. If using custard cups, place on a baking sheet.
Bake in a 350 degree F oven for 25 to 30 minutes or until a wooden toothpick inserted near the center comes out clean. Cool on a wire rack for 5 minutes. Loosen sides and invert the cake onto a plate. Serve cake warm with whipped cream or ice cream. Serves 4.
Soup and an assortment of crackers are a good prelude to this delectably delicious cake.