• Preheat oven to 400 degrees and line a 12-cup muffin tin with muffin liners (the foil ones are my favorite, but any will do).

Muffins:

• In a large bowl, mix flour, granulated sugar, brown sugar, baking powder, baking soda, espresso powder, and salt together.
• Make a well in the center of the dry ingredients (push the dry ingredients up around the sides so there’s a hole or ‘well’ in the center—this helps disperse the wet ingredients better).
• Pour in the buttermilk, oil, brewed coffee, and eggs.
• Gently mix the batter until the wet ingredients are just mixed in (the batter will still be very dry at this point).
• Add in the sour cream and vanilla extract, and mix until all of the ingredients are just combined.
• Lastly, add in the mini chocolate chips and mix until combined.
• Fill the muffin tins about 2/3 of the way full with the batter. The batter makes about 12-14 muffins.

Cinnamon Sugar:

• Mix the sugar and cinnamon together. Sprinkle on top of each of the muffins cups.

Crumb Cake Topping:

• Mix all purpose flour, brown sugar and cinnamon together.
• Add in the melted butter and mix with a fork until the mixture comes together and forms crumbs.
• Generously sprinkle the crumb cake topping over each muffin, pressing the crumbs gently into the batter (to keep them from falling off in the oven as the muffins bake).
• Bake muffins for 15-17 minutes, or until a cake tester comes out clean.
• If desired, you can sprinkle more mini chips on top of the muffins, or you can dust the muffins with powdered sugar.
• Enjoy!