Yummy, yummy, yummy. We love these hot from the oven with lemon butter (softened butter creamed with a little lemon zest).
Preheat oven to 350 degrees F. Line muffin pans with paper liner.
In a bowl of an electric mixer fitted with the paddle attachment, cream the butter and sugar until light and fluffy, about 5 minutes. With the mixer on low speed, add the eggs one at a time, then add the vanilla, sour cream, and milk. In a separate bowl, sift the dry ingredients. With the mixture on low speed add the flour mixture to the batter and beat until just blended. Fold in the blueberries with a spatula and be sure the batter is completely mixed.
Scoop the batter into prepared muffin tins, filling each cup just over the top, and cake for 25 to 30 minutes, until the muffins are lightly browned on top and a cake tester comes out clean.