First, melt the butter (either in a pot on a small flame or in your microwave) , then let it cool down for a few minutes.
Beat the eggs with the sugar, using the hand mixer, for at least 4-5 minutes (so the sugar will melt)
Add the melted butter into a large bowl, add the egg mixture to it and mix again.
Now set your hand mixer aside and, using a spoon, add the flour, baking powder and little by little, pour the milk while you begin folding your dough. Make sure you incorporate all the flour and milk until you obtain a runny dough.
Spray your muffin tray with a bit of oil, or use muffin paper cups if you have them on hand, and pour about 2 tablespoons of muffin dough in each muffin hole.
Bake for about 20 minutes, at 350°F (180°C).
Let your muffins cool down before serving, then sprinkle with powdered sugar. Enjoy!