Cocoa powder can be used in place of chocolate or baking chocolate in many recipes. A number of recipes call for baking chocolate, which is essentially cocoa and fat. Typically, baking chocolate is unsweetened; thus, when using cocoa powder as a substitute, there's no need to add sugar. If a recipe calls for melted sweetened chocolate such as chocolate chips, you'll need to add sugar to the cocoa powder to obtain the necessary sweetness.
Measure the cocoa powder and sugar. For 28.4gr. of unsweetened chocolate, you'll need 3 tbsp of cocoa powder and 1 tbsp of butter, vegetable oil or shortening. For one cup of chocolate chips, you'll need 6 tbsp of cocoa powder, 7 tbsp of granulated sugar and 1/4 cup butter, vegetable oil or shortening.
Mix the cocoa powder and fat, or cocoa powder, fat and sugar if your recipe calls for sweetened chocolate. Combine thoroughly until the mixture resembles melted chocolate.
Add the chocolate mixture. Follow the recipe just as you would if using melted chocolate.