Cinnamon Streusal Blueberry Muffins

I found this recipe on allrecipes and it is truly one of the best blueberry muffins I've ever had. These are just like the Einstein Bagel Blueberry Muffins. They are to die for!

3 cups all-purpose flour 1 1/2 cup white sugar 1 teaspoon salt 4 teaspoons baking powder 2/3 cup vegetable oil 2 eggs 2/3 cup milk 2 cups fresh blueberries Crumb Topping: 1/2 cup white sugar 1/3 cup all-purpose flour 1/4 cup butter, cubed 1 1/2 teaspoons ground cinnamon

1.	Preheat oven to 400 degrees F (200 degrees C). Grease muffin cups or line with muffin liners.
2.	Combine flour, sugar, salt and baking powder. Place vegetable oil into a 2 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 with crumb topping mixture.
3.	To Make Crumb Topping: Mix together sugar, flour, butter, and cinnamon. Mix with fork, and sprinkle over muffins before baking.
4.	Bake for 20 to 25 minutes in the preheated oven, or until done.