1. Heat oven to 375 degree F. Lightly coat twelve 2-1/2-inch muffin-pan cups with cooking spray. Set aside.
2. In a medium bowl, whisk together 3 cups flour, sugar, baking powder, baking soda, salt, and cinnamon. In a large bowl, whisk butter, eggs, and espresso powder until smooth. Stir in half of flour mixture just until moistened. Stir in half of buttermilk and half of remaining flour mixture; then stir in remaining buttermilk and flour mixture. Divide batter between prepared cups.Make topping::
3. Combine 1/4 cup flour, sugar, and cinnamon; cut in butter and squeeze mixture to form clumps. Sprinkle mixture on muffins. Bake muffins until a toothpick inserted in center comes out clean, 25 minutes. Cool in pan on wire rack 5 minutes, then transfer muffins to rack to cool. Makes 12 muffins.