Preheat the oven to 400°F. Line oversized muffin molds with liners. You can also line regular muffin pans. Makes about 12 oversized or 24 regular.
In a large mixing bowl, whisk together flour, sugar, baking powder, baking soda, salt.
In a medium-sized mixing bowl, whisk together the eggs, milk, vanilla, Nutella and vinegar. Add the wet ingredients, along with the melted butter, to the dry ingredients, stirring until all ingredients are combined. The batter will still be a little lumpy.
Scoop the batter into the prepared muffin tin about 2/3 full. Bake the muffins for about 25 minutes for oversized muffins (about 18 minutes for regular), or until a knife inserted in the center of a muffin comes out clean.
The nutrition information provided are only estimates based on an online nutritional calculator. This is not a comprehensive list of all the nutrients in the recipe (i.e., does not include vitamins, cholesterol, etc). I am not a certified nutritionist. Please consult a nutritionist or doctor for accurate information and any dietary restrictions and concerns you may have.