Blueberry Coffee Cake Muffins or Chocolate Chip

12 tablespoons (1 1/2 sticks) unsalted butter, at room temperature
1 1/2 cups sugar
3 extra-large eggs, at room temperature
1 1/2 teaspoons pure vanilla extract
8 ounces (about 1 cup) sour cream
1/4 cup milk
2 1/2 cups all-purpose flour
2 teaspoons baking powder
1/2 teaspoons baking soda
1/2 teaspoon salt
2 half-pints fresh blueberries, picked through for stems
or 1 bag of mini chocolate chips

Preheat the oven to 350 degrees F. Spray muffin pans with Pam.

Cream the butter and sugar until light and fluffy, about 5 minutes. With mixer on low speed, add the eggs 1 at a time, then add the vanilla, sour cream, and milk. In a separate bowl, sift together the flour, baking powder, baking soda, and salt. With mixer on low speed add the flour mixture to the batter and beat until just mixed. Fold in the blueberries with a spatula and be sure the batter is completely mixed.
Scoop the batter into the prepared muffin pans, filling each cup just over the top, and bake for 25 to 30 minutes, until the muffins are lightly browned on the top and a cake tester comes out clean.