Preheat oven to 400°F. Grease muffin cups or line with muffin liners.
Combine 1½ cups flour, ¾ cup sugar, salt and baking powder. Place vegetable oil into a 1-cup measuring cup; add the egg and enough milk to fill the cup. Mix this with the flour mixture. Fold in blueberries.
Mix together ½ cup sugar, ⅓ cup flour, ¼ cup butter, and 1½ teaspoons cinnamon. Mix with fork.
Fill muffin cups right to the top, and sprinkle with crumb topping mixture.
Bake for 20–25 minutes, or until done.
Notes
Aluminum foil helps keep food moist, ensures it cooks evenly, keeps leftovers fresh, and makes clean-up easy.