Preheat oven to 425.
Spray 4 (3/4 c.) soufflé cups with non-stick cooking spray and place on cookie sheet.
Microwave butter and chocolate chips until melted. Whisk.
Whisk in sugar.
Whisk in eggs and eggs yolks.
Bake 13-14 minutes. Let stand one minute before inverting to plate.
* cakes can be made up to 24 hours in advance and stored in refrigerator. Let stand at room temperature 20 minutes before baking.