Melted unsweetened chocolate is often one of the key ingredients to baking gooey brownies and decadent chocolate cakes. In a pinch, you can substitute unsweetened cocoa powder (not a sugary cocoa mix)—you just need to add butter, shortening or a flavorless oil like canola.
Melt butter or shortening in a double boiler over low heat, stirring continuously, or in a microwave for 10-second intervals, stirring in between each interval.
Stir the unsweetened cocoa powder into the melted butter or shortening until smooth.
Use as directed in the recipe.
Check for freshness of cocoa powder before using, and make sure to store in a tightly closed tin away from light.