Preheat oven to 350F/180C. Grease a mini muffin pan with butter or cooking spray.

In a large bowl sift together flour, baking powder, cinnamon, nutmeg, and salt. Set aside.

In the bowl of a standing mixer fitted with the paddle attachment, beat together butter and sugar on medium speed for 3 minutes. Scrape down the sides and bottom of the bowl as necessary. Beat in egg, vanilla extract, and milk until combined. Reduce mixer speed to low and add half of the flour mixture until combined, followed by the other half. Do not overmix—the less you mix, the lighter the muffins will be.

There are two ways to fill the muffin tin: Option 1: Spoon about 1 tablespoon of batter into muffin cavity. Layer with ½ teaspoon Nutella in the center and spoon more batter on top to cover the Nutella and fill the muffin cup about ¾ full. Option 2: Use two pastry bags, filling one with batter and the other with Nutella. Pipe some of the batter into each tin, then pipe some Nutella into the center. Use the rest of the batter to cover the Nutella and fill the cups about ¾ full.

Bake for about 10 minutes, until a toothpick inserted into the muffin comes out clean. Allow muffins to cool for about 5 minutes, then remove from pan and allow them to cool completely on a wire rack.

While muffins are cooling, make the cinnamon-sugar topping. In a small bowl mix together sugar and cinnamon. For each cupcake, dip the top in melted butter, then dip into the cinnamon-sugar mixture, swirling around to get a thick coating.

Muffins are best the same day they are made, but will also freeze well for up to 2 months.