Preheat oven to 400. Grease a 12 count muffin pan (if not using liners).
Combine flour, sugar, salt, and baking powder in a large mixing bowl.
In another small mixing bowl, whisk together egg, vegetable oil and milk.
Add liquid mixture to dry ingredients, and whisk together until blended.
Fold in blueberries.
Fill the muffin cups, but not quite to the very top.
Make the crumb topping by mixing sugar, flour, and cinnamon. Add a small sliver of butter and mash with a fork or pastry blender. Try to get it to a crumb consistency, but if too much butter is added it will turn too pasty and not work.
Sprinkle the crumb topping on each muffin.
Bake for 17 to 24 minutes, until a toothpick comes out clean.