Combine 1 1/2 cups flour, 3/4 cup sugar, salt and baking powder.
Place vegetable oil into a 1 cup measuring cup; add the egg and add enough milk to reach the 1-cup mark.
Mix this with flour mixture.
Fold in blueberries.
Fill muffin cups right to the top, and sprinkle with crumb topping mixture.
To Make Crumb Topping: Mix together 1/2 cup sugar, 1/3 cup flour, 1/4 cup butter, and 1 1/2 teaspoons cinnamon. Mix with fork, and sprinkle over muffins before baking.
Bake for 20 to 25 minutes in the preheated oven, or until done.
Tips
These muffins are extra large and yummy with the sugary-cinnamon crumb topping. I usually double the recipe and fill the muffin cups just to the top edge for a wonderful extra-generously-sized deli style muffin.