Adjust an oven rack to the middle position and heat the oven to 375 degrees. Line a muffin tin with liners.

Whish the flour, sugar, baking powder,baking soda and salt together in a large bowl.

In a medium bowl, whisk the milk and eggs together until smooth.

Add the espresso powder and whisk until combined.

Gently fold the buttermilk mixture into the flour mixture with a spatula until combined.

Fold in the melted butter.

Fold in the chocolate chips

Divide the batter evenly among the muffin cups.

Bake until golden brown, 25-30 minutes, and a toothpick inserted in the center comes out with only crumbs.

Let cool in pan for 5 minutes before removing and placing on a wire rack to cool completely.