• Preheat the oven to 400 degrees F. Grease muffin cups or line with muffin liners.
• Combine flour, sugar, salt and baking powder in the bowl of a stand mixer. 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 the flour mixture.
• Fold in blueberries.
• Fill muffin cups right to the top, and sprinkle with crumb topping mixture.

For Topping

• Mix together sugar, flour, butter, and cinnamon with a fork. Sprinkle over muffins before baking.
• Bake for 20 to 25 minutes in the preheated oven, or until the toothpick comes out clean.