To Die for Blueberry Muffins

1 1/2 cups all-purpose flour
3/4 cup sugar
1/2 cup salt
2 teaspoons baking powder
1/3 cup vegetable oil
1 large egg
1/3 cup milk
1 cup fresh blueberries
1/2 cup sugar
1/3 cup flour
1/4 cup butter -- cubed
1 1/2 teaspoons ground cinnamon

Preheat oven to 400 degrees. Grease muffin cups or line with liners. Combine 1 1/2 cups flour, 3/4
cup sugar, salt and baking powder. Place oil into a 1 cup measuring cup ; add the egg and enough milk to fill the cup. Mix this with flour mixture. Fold in blueberries. Fill muffin cups right to the top, and sprinkle over muffins before baking. Bake for 20-25 minutes or until tests done.