Preheat your oven to 400°F / 200°C. Generously grease a standard 12-cup muffin tin with butter or line it with paper muffin cups.
In a large bowl, use an electric mixer or a wooden spoon to cream the room temperature butter and sugar together until light and fluffy.
In a separate medium bowl, whisk together the all-purpose flour, baking powder, and salt.
In a small bowl or measuring cup, lightly beat the eggs with the milk.
Add about one-third of the dry flour mixture to the creamed butter and sugar, mixing on low speed until just combined.
Pour in about half of the milk mixture and mix again.
Repeat, alternating between the dry and wet and ending with the dry .
Mix only until the flour disappears; the batter should be thick, lumpy, and moist.
Carefully spoon the batter into the prepared muffin cups, filling them about two-thirds full for medium muffins or nearly to the top for larger, bakery-style muffins. Handle the batter as little as possible.
Bake for 20 to 30 minutes, until the muffins are golden brown and a toothpick inserted into the center of one comes out clean.
Let the muffins rest in the tin for 5 minutes before transferring them to a wire rack to cool slightly.
Serve warm and enjoy!
Do not overmix the batter! A few lumps are perfect. Overmixing develops gluten, which leads to tough, dense muffins instead of tender ones.
