Prepare a muffin tin by spraying with non-stick spray or line with paper cupcake liners. Set aside.
Combine the first six ingredients in a mixing bowl.
In a separate bowl, mix together coffee, buttermilk, egg, butter and vanilla. Add to flour mixture and stir together.
Add chocolate chips and mix well.
Spoon the muffin batter into muffin tin, filling about 2/3 full.
Bake on center rack of oven approx. 20 minutes. Depending on your oven, time may be plus or minus this amount. Start checking muffins at 17 minutes by inserting a toothpick into the center of a muffin. They are done when the toothpick comes out clean.
Cool in pan for 5 minutes, then remove muffins to a wire rack to continue to cool.