Put butter or margarine and chocolate chips in a small, microwave-safe bowl. Cook in the microwave for 45 seconds. Stir and cook for 30 seconds. Stir and continue cooking for 30 seconds at a time until chocolate is completely melted. Set aside.
Beat together sugar, eggs and vanilla until fluffy. Stir in melted chocolate. Add flour, salt and baking powder until combined. Refrigerate dough for at least 2 hours for easier handling.
Using a tablespoon of dough at a time, roll into balls and roll through powdered sugar, making sure to coat completely. Bake at 325 degrees for 8 to 10 minutes.