Melt butter. Mix with oil.
Mix in sugar, eggs and vanilla.
Combine flour, baking powder, salt and cocoa powder and sift. I always use this kind of sifter.
Add dry mixture to wet and stir.
Add in chocolate chips if you are using them.
Spray a mini cupcake pan or grease with butter or oil
Use a cookie scoop or tablespoon and fill 3/4 full.
Bake at 350 degree F for 15 minutes.
Let cool completely before removing.