n Preheat oven to 350° and line a 12 cup muffins tin with cupcake liners (my batter made more like 16-17 muffins).n n In a medium bowl combine flour, baking powder, and salt.n n In the bowl of a stand mixer, cream together the butter and sugar. Add eggs, one at a time. Add mashed banana. Mix until everything is well combined and scrape down the side of the bowl.n n Incorporate the dry ingredients a little at a time until everything is thoroughly combined.n n Fill your muffins cups about 2/3 to the top. Microwave your chocolate hazelnut spread in a small bowl for about 10-12 seconds (this is completely optional, but it was a heck of a lot easier to swirl into the batter this way). Add 1 tsp chocolate hazelnut spread to the top of each batter-filled muffin cup. With a toothpick, swirl the two together until you're happy with the way your swirls look.n n Bake for 22 minutes (if you wind up making mini loafs, which I did, bake for 28-30 minutes until a tester comes out clean).n