1Preheat oven to 375 F. Sift flour and mix with the dry ingredients including cocoa, chocolate chips, and orange zest. Set aside.
2Mix together the butter, sugars, sour cream, milk, eggs and coffee. Fold into dry ingredients, just until moistened and smooth. Be careful not to overmix. Place liners in 12 muffin cups and bake approximately 20-25 minutes.
Whip the butter. Add sugar, vanilla and milk. Mix together until well blended into a smooth icing. Smooth glaze over the top of cooled muffins.