Preheat oven to 400° F and line a 12 count cupcake tin with liners or spray with nonstick baking spray.
In a medium sized mixing bowl, mix together the flour, espresso powder, flaxseed, baking soda, baking powder and salt. Set aside.
2 cups All-Purpose Flour, 2 tsp. espresso powder, 1 Tbsp. ground flaxseed, 1 tsp. baking soda, 1 tsp. baking powder, 1/2 tsp. salt
In another mixing bowl, whisk together bananas and sugar. Then whisk in the oil, eggs, brewed coffee and coffee extract. Then gradually mix in the flour into the wet mixture. Dough will be thick.
2 large over ripe bananas, mashed, 1 cup sugar (I use 1/2 brown, and 1/2 granulated white), 1/3 cup vegetable oil, 2 large eggs, 1/3 cup freshly brewed black coffee, 2 tsp. coffee extract
Fill each muffin tin about half way. Place ~1-2tsp. of Nutella in the middle and then top the muffin with more muffin batter. Dollop a little more Nutella on the top and swirl with a toothpick or butter knife.
Nutella
Bake for 15-17 minutes or until a toothpick inserted in the center comes out clean. Cool for a few minutes, then enjoy!