-
Preheat oven to 375ºF. Line muffin tin with muffin cups and set aside.
-
In a large bowl, mix the flour, baking soda, baking powder, nutmeg, cinnamon, and salt.
-
In another bowl, mix together the bananas, sugar, egg, vanilla, and butter.
-
Add the banana mixture to the flour mixture and stir, just until moistened. Spoon the batter into the prepared muffin tins, about 2/3 of the way up.
-
Heat the nutella in the microwave for about 30 seconds, just to soften it up and make it a little runnier. Spoon about a tsp. of Nutella atop each muffin and swirl it with a toothpick to mix it in.
-
Bake for 12-13 minutes.
-
Meanwhile, in a small bowl, mix together the flour, brown sugar, and cinnamon. Cut in the butter with a pastry blender or fork.
-
After your 12-13 minutes are up, sprinkle the streusel on top of the muffins and continue baking for another 5-7 minutes, or until an inserted toothpick comes out clean.