You can melt chocolate in a double boiler or in a microwave. If using a double boiler, be sure the water in the bottom pan does not touch the base of the top pan and that it never boils. Any moisture, including steam, that comes in contact with the chocolate could cause it to seize into a lumpy mass. (To save seized chocolate, whisk in vegetable oil or solid vegetable shortening, 1 tsp. at a time, until smooth.) If microwaving the chocolate, check it every 30 seconds to avoid scorching. When the chocolate is shiny and soft, remove it and stir until smooth.

Almond paste makes the cake a bit sticky, so be sure to coat the wax paper in the pan with cooking spray and dust with flour before spooning in the batter. Combining the almond paste and sugar in a blender or food processor helps incorporate the paste into the batter without lumps. This cake can be made a day in advance; just wrap it in plastic wrap, and store in the fridge.