Preheat oven to 350°F. Spray a standard muffin pan with non-stick cooking spray and set aside.
Mix the butter and sugar in a large mixing bowl until creamy (takes about 5 minutes with mixer on medium speed). Add in the eggs, milk, and vanilla and mix until well blended (about 2 minutes with mixer on slow-medium speed).
Add dry ingredients and mix until well blended (about 2 minutes with mixer on slow-medium speed).
Fill muffins cups about 3/4 full.
Place in the pre-heated oven and bake for 15 minutes. Check for doneness by inserting a wooden toothpick into the center of a muffin. If the toothpick comes out clean or with a tiny bit of batter on it, the muffins are ready to come out of the oven. If there is a lot of batter on the toothpick, bake for another minute and check again. The goal is not to overbake the muffins or they will be dry. Remove from oven and cool for at least 5-10 minutes before eating.
Optional: cool muffins completely and sprinkle with powdered sugar or add a dollop of whipped cream