Preheat your oven to 180°C (350°F), then line your muffin tins with paper.
Sift and combine the dry ingredients: flour, baking soda, baking powder, and salt.
Combine sugar and butter in another bowl.
Mix until creamy, then add the eggs --- one at a time.
Add the milk and vanilla extract, then mix to combine evenly.
Add the strained, dry ingredients from earlier and mix just enough to combine.
Place a tablespoon of the batter into each muffin tin.
Add about a heaping half teaspoon of Nutella on top of the batter.
Cover with the remaining batter.
Add a couple of dots of Nutella, then use a toothpick to swirl it around.
Place your tray of Nutella muffins in the middle of the oven for twenty to twenty-five minutes, or until a toothpick comes out clean when you insert it in one of the muffins.
Remove from the oven and transfer to a rack to cool.
Sprinkle with powdered sugar, if preferred --- then enjoy!