Preheat oven to 425 degrees Fahrenheit. Generously grease a muffin pan and set aside.

Mix milk, sour cream, oil, butter, eggs, and vanilla until smooth. Add flour, sugar, baking powder and salt. Mix until just combined. The mixture will be thick; try not to overmix. Fold in the blueberries.

In a separate bowl, mix flour, sugar, and butter to form the crumb topping.

Scoop batter into the prepared muffin pan, filling each until the top. Sprinkle with crumbs. Bake for seven minutes, then reduce oven temperature to 350 degrees Fahrenheit and bake for another 14 minutes, or until a toothpick comes out clean.