Half fill the muffin cases with batter, then spoon a teaspoon of nutella on top of the batter
1.5 cups Nutella
Fill the rest of the muffin case with batter, enclosing the nutella inside. For extra large 'mushoom' shaped muffins, fill the batter all the way to the top of the liners
Put another small dollop of nutella on top of the muffins and swirl into the batter with a toothpick
Bake for 20 minutes or until golden brown and a toothpick comes out clean (make sure you avoid the nutella when testing)
Let cool in the muffin tray before attempting too move the muffins as they will be fragile and may break if moved while hot