Preheat oven to 350 degrees.

In a medium bowl, cream together butter and sugar with an electric mixer. Add in eggs and mix until incorporated. Add in vanilla extract and mix another 30 seconds.

In a separate bowl, combine flour, cocoa powder, salt and baking powder.

Slowly add dry ingredients to the wet ingredients, 1/2 cup at a time, mixing well after each addition. Once the ingredients are incorporated, fold in white chocolate chips.

Drop by rounded tablespoon onto a greased baking sheet, and bake in preheated oven for 10 - 15 minutes.