Preheat oven to 400°F (200°C). (Make sure your oven rack is toward the bottom of the oven as this cake will rise significantly, and if it’s too close to the top element it will burn.)

In the bowl of an electric mixer, beat the egg whites until stiff. Slowly add the sugar and beat until stiff peaks form. Fold in remaining ingredients, including the yolks, in the order they appear. Pour into a large tube pan that does not have a nonstick coating.

Bake for 40–45 minutes or until the cake springs back when lightly touched. Remove from the oven and place upside down on the legs of the pan, or else invert the pan on the neck of a tall, slender bottle to cool and to prevent it from falling.

Melt the chocolate and the margarine in a double boiler.

Meanwhile, dissolve the coffee granules in the boiling water. Add the cocoa powder to the dissolved coffee and stir until there are no more lumps.

Add the sugar to the melted chocolate. Mix well, and add the coffee mixture as well. Remove from heat and quickly whisk in the eggs. Let cool to room temperature before pouring on the cake.