1Heat oven to 400°F. Line 12 regular-size muffin cups with paper baking cups, or spray bottoms only of cups with cooking spray.
2In medium bowl, stir 1/4 cup flour, the brown sugar and cinnamon until mixed. Cut in butter, using pastry blender or fork, until mixture is crumbly; set aside.
3In large bowl, beat milk, oil and egg with fork or wire whisk until blended. Add 2 cups flour, the granulated sugar, baking powder and salt all at once; stir just until flour is moistened (batter will be lumpy). Gently stir in blueberries. Divide batter evenly among muffin cups. Sprinkle each with about 1 tablespoon streusel.
4Bake 20 to 25 minutes or until golden brown. If muffins were baked in paper baking cups, immediately remove from pan to cooling rack. If muffins were baked in sprayed pan, leave in pan about 5 minutes, then remove from pan to cooling rack. Serve warm or cooled.