3 1/2 cups flour 1/2 cup sugar 4 teaspoons baking powder 1/2 teaspoon salt 1 1/2 cup milk 1/3 cup vegetable oil 1/3 cup fat-free sour cream 2 eggs, beaten 4 cups fresh or frozen blueberries, unthawed if frozen 4 tablespoons sugar 8 ounces dried cranberries
Line muffin cups with paper liners and set aside. Preheat oven to 400 degrees F.
In a large mixing bowl, combine flour, 1/2 cup sugar, baking powder and salt and stir to mix. Combine milk, oil and eggs in a medium bowl and beat with a wire whisk until blended.
Make a well in dry ingredients and pour the liquid ingredients into the well all at once. Stir until just moistened. In a medium bowl, combine 4 Tbsp. sugar and blueberries and toss to coat with sugar. Stir gently into batter just until blueberries are distributed.
Spoon batter into muffin cups, filling 1/4 full. Bake at 400 degrees F for 20-25 minutes, until light golden brown and firm to the touch. Let cool on wire rack 3-4 minutes, then remove muffins from pan and cool completely on wire rack. Store tightly covered at room temperature.