Preheat oven to 400 degrees. Grease muffin cups or line with muffin liners. Combine 1 1/2 cuups flour, 3/4 cup sugar, salt and baking powder. Place vegetable oil into a 1 cup measuring cup; add the egga nd enough milk to fill the cup. Mix this with flour mixture. Fold in blueberries. Fill the muffin cups right to the top, and spinkle with crumb toppin mixture.
To make crumb toppin: 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 20-25 minutes in the preheated oven, or until done.