preheat oven to 375 degrees.

Spray muffin top pan or regular muffin pan with nonstick cooking spray.

In a medium bowl combine flour, granulated sugar, brown sugar,cocoa powder, baking powder, baking soda and salt.

Stir in chocolate pieces.

Make a well in the center of the flour mixture.

In a small bowl whisk together oil, milk, vanilla and egg. Add oil mixture all at once to flour mixture.

Stir just until moistened and all flour is incorporated.

Spoon batter into prepared pan.

Bake for 10-12 minutes if using a muffin top pan or 18-20 minutes if using a regular muffin pan.

Cool in pan on wire racks for 5 minutes. Remove from pan and allow to cool completely before storing.