JUMBO BLUEBERRY MUFFINS
3 cups all-purpose flour
3 teaspoons baking powder
1/4 teaspoon baking soda
1/2 teaspoon ground cinnamon (optional)
1/2 teaspoon salt
5 Tablespoons unsalted butter
1/3 cup vegetable oil
1 cup granulated sugar
2 large eggs
1/3 cup sour cream or yogurt
1 cup milk
1 teaspoon pure vanilla extract
1 and 1/2 cups fresh or frozen blueberries (do not thaw)
optional: coarse sugar for sprinkling
