Mix butter, sugar, and eggs together in a large bowl. Put sour cream into a medium sized bowl, add baking powder and sugar. Watch it rise, it's really cool! Add the sour cream mix into the butter mix. Gradually add flour, then dump in the chocolate chips. Stir it all up, and then pour into muffin pans, filling them about halfway. Bake for 25 minutes. They are best warm, and make great breakfast additions.
Put a spin on it: Bake in a 9 x 12 bread pan for 50 minutes.