These were so good, I have no pictures! The mocha flavor wasn't as pronounced as I'd like with just coffee, so perhaps I'll try a double-brew espresso next time.

1/4 strong espresso, cooled
1/2 cup buttermilk
1/3 cup vegetable oil
2 large eggs
1 tsp vanilla extract
1 3/4 all purpose flour
1/4 cup granulated sugar
1/2 cup packed brown sugar
1 tsp salt
1 tsp baking powder
1 tsp baking soda
1 cup milk chocolate chips
1 cup chopped, toasted pecans

Preheat oven to 350 degrees. Whisk together wet ingredients; espresso, buttermilk, oil, eggs and vanilla.  In another bowl, mix dry ingredients: flour, sugars, cocoa, baking powder, baking soda and salt.  Stir wet into dry ingredients roughly, then mix in chocolate chips and pecans.  Divide batter equally in muffin tins, about 2/3 full. Bake 25 minutes, rack and cool.

Adapted from this Epicurious recipe.