In the bowl of an electric mixer fitted with the paddle attachment, cream butter and 1 cup of the sugar until light and fluffy, 2-3 minutes. With the mixer on low speed, add the eggs, one at a time, then add vanilla, sour cream, and milk.
In a separate bowl, sift flour, baking powder, baking soda, and salt together. With the mixer on low speed, add the flour mixture to the batter, and beat until just mixed. Fold in the blueberries gently with a spatula, and make sure batter is well mixed.
In a small bowl, stir the brown sugar, cinnamon, and remaining tbls. of white sugar together.
Scoop the batter into the prepared muffin tin, filling each cup just over the top, and bake 10 minutes.
Remove from oven, sprinkle with the brown sugar and cinnamon topping, and bake 10-15 more minutes, until the muffins are lightly browned on top and a toothpick stuck into the middle of the muffin comes out clean.