Dutch process cocoa means that it has been processed with an alkali (potassium carbonate) giving it a neutral PH. This affects the cocoa's interaction with leavening agents making it neutral meaning it does not react with baking soda; so unless the recipe calls specifically for dutch process cocoa use natural cocoa powder. If wondering how to check for this just look at ingredients on the back of container. Natural cocoa powder has only one ingredient which is you guessed it- cocoa powder. Where as dutch process cocoa has two ingredients, cocoa and bicarbonate of soda (AKA baking soda) or label will say 'cocoa processed with alkali'