These Bakery Style Blueberry Muffins are loaded with blueberries and have an irresistible cinnamon sugar topping!
Preheat oven to 400 degrees.
In large bowl add egg, oil and milk and whisk together.
For the crumb topping, place the sugar, flour and cinnamon in a medium bowl. Whisk together. Add the cooled butter and mix together with a fork until crumbly. Sprinkle over each muffin before baking. Bake for 5 minutes at 400 degrees and then turn the oven down to 350 degrees and continue baking for 13 minutes or until a tester inserted in center of muffin comes out clean. Remove from oven and cool on wire rack.