Preheat your oven to 350 degrees. Prepare 2 - 12-cup muffin pans with cooking spray. Set aside.
In a large mixing bowl combine flour, baking powder, salt and 1 tablespoon espresso powder.
In a large measuring cup combine all of the coffee, buttermilk and vanilla. Set aside.
Ideally using an electric mixer, stand or handheld, beat together 1 ½ cups of the softened butter with 2 cups sugar until fluffy, just a few minutes.
Add eggs and beat until incorporated.
Gently beat the flour and coffee mixtures into the butter mixture until fully incorporated. I alternate back and forth between wet and dry ingredients until all of the ingredients are blended together. Scrape down the sides of the bowl as necessary.
Scoop the batter into each of the greased muffin cups, until about ¾ full.
Place the pan in the oven and bake until the muffins have risen and a toothpick inserted in the middle comes out clean, 25 to 30 minutes. Rotate the pan halfway through for even baking.
Remove the muffins from the oven and allow them to cool completely in the muffin pan.
Meanwhile, in a medium sized bowl, combine the remaining sugar and espresso powder. Melt butter into a small, deep cup that you can dip each cooled muffin into or dip your brush into.
Brush or dip the cooled muffins on all sides with the melted butter and roll in the sugar/espresso mixture. Serve immediately with or without coffee! These are delicious! Enjoy!