Cocoa Powder or Unsweetened Chocolate

Can cocoa powder be substituted for unsweetened chocolate?

Cocoa powder is unsweetened chocolate from which 76 to 90 percent of the cocoa butter has been removed. It is generally called for when a big hit of chocolate flavor is desired without any additional fat, usually in recipes that already contain a lot of butter, such as cakes and cookies. Some cocoas are packaged with instructions indicating that 3 tablespoons of cocoa powder combined with 1 tablespoon of vegetable oil can be substituted for 1 ounce of unsweetened chocolate. To find out if this substitution works, we prepared batches of brownies made with the 6 ounces of unsweetened chocolate called for in the recipe and with the cocoa and oil substitution. To our surprise, tasters found no textural differences between the two batches.