1Heat oven to 400°F. Place mini paper baking cup in each of 24 mini muffin cups.
2In medium bowl, mix flour, sugar, cocoa, baking powder, baking soda and salt with whisk. In small bowl, mix buttermilk, oil, vanilla and egg with whisk. Add buttermilk mixture and chocolate chips to flour mixture, stirring gently until blended. Divide batter evenly among muffin cups, filling full.
3Bake 12 to 14 minutes or until top springs back when touched lightly in center. Cool 5 minutes; remove from pans to cooling rack. Cool completely, about 10 minutes.