In a medium bowl, mix sugar and butter until smooth. You can mix by hand or using a hand mixer.
Add egg, vanilla, and milk.
Add flour, sifted with baking powder and salt.
Fold in blueberries last.
Divide the batter between muffin cups and bake for 20 minutes at 375F.
Remove muffins from the baking pan right away onto a cooling rack.
Serve warm or at room temperature.
Notes
Ingredients and their substitutes:Fat: You can use butter or shortening.Egg: Bring the egg to room temperature before using it. Cold eggs shock the batter and make it thicker. If you forgot to take the egg out of the refrigerator, place the egg in warm water for 10 minutes, then use it.Blueberries: You can use either fresh or frozen. Blueberries can be replaced with other berries, like strawberries, blackberries, raspberries or even cranberries.Flour: All purpose flour is the choice for this recipe.Storage: Most muffins are at their best when consumed the same day. Store the leftovers in an airtight container for up to 3 days.They are good when you reheat them in the microwave for a few seconds and serve with butter.