Chocolate-Graham Muffins

Preheat oven to 400 degrees F. Coat 12 muffin cups with cooking spray.

Pulse graham crackers into crumbs in a food processor or place in a large plastic bag and crush with a rolling pin. Whisk all-purpose flour, whole-wheat flour, cocoa, baking powder, baking soda and salt in a large bowl. Stir in graham cracker crumbs.

Whisk eggs, brown sugar and granulated sugar in a medium bowl until smooth. Add buttermilk, oil, coffee and vanilla and whisk until blended. Make a well in the dry ingredients; add the wet ingredients and stir with a rubber spatula until just combined. Gently fold in chocolate chips. Spoon the batter into the prepared muffin cups.

Bake the muffins until the tops spring back when touched lightly, 15 to 25 minutes. Let cool in the pan for 5 minutes. Loosen edges and turn muffins out onto a wire rack to cool.