Preheat the oven: Begin by preheating your oven to 180°C (350°F). This will help achieve that perfect bakery-style muffin texture.
Prepare the muffin tin: Line a muffin tin with paper liners to make removal and clean-up a cinch.
Cream the butter and sugars: In a large mixing bowl, cream together the soft butter, sugar, and vanilla sugar until the mixture is light and fluffy. This step is key to creating a tender muffin.
Add eggs: Beat in the eggs, one at a time, ensuring each egg is fully incorporated before adding the next.
Mix the dry ingredients: In a separate bowl, combine the flour, baking powder, and salt.
Combine the mixtures: Gradually add the dry ingredients to the creamed mixture, alternating with the milk. Mix until just combined, being careful not to overmix.
Add Nutella: Gently fold in generous swirls of Nutella into the batter without fully blending—this creates those beautiful chocolatey pockets.
Fill the muffin liners: Spoon the batter into the prepared muffin liners, filling each about 2/3 of the way full.
Bake: Bake in the preheated oven for 20-25 minutes, or until a toothpick inserted into the center comes out clean.
Cool and enjoy: Let the muffins cool slight in the pan before transferring them to a wire rack. Enjoy warm or at room temperature!