Preheat oven to 350 degrees. Line muffin pans with paper liners.
Beat the butter and sugar together in the bowl of an electric mixer until light and fluffy. Beat in eggs one at a time, then mix in vanilla, sour cream, and milk.
In a separate bowl sift together flour, baking powder, baking soda and kosher salt.
With the mixer on low speed add in the dry ingredients until combined.
Using a spatula, gently stir in the blueberries.
Spoon the batter into prepared muffin cups and bake for 25-30 minutes, or until a toothpick comes out clean.