Moist muffins that are loaded with banana and blueberry flavor. Then topped with a cinnamon crumb topping.
Preheat Oven to 350℉
In a mixing bowl combine the oil, sugar, eggs, milk, vanilla extract, and mashed bananas until combined.
Beat in the sifted flour, baking soda, baking powder, and salt into the banana mixture. Mix until all are combined.
Gently fold in the blueberries and walnuts. Either line a muffin tin with cupcake liners or spray with baking spray. Fill a muffin cup ¾ full or use a 2-inch cookie scoop to fill the muffin cups. Leaving enough room in each muffin cup for the crumb topping.
In a bowl melt the butter. Add to the butter mixture the flour, sugar, and cinnamon. Combine until crumbs form.
Sprinkle 1 tablespoon of the crumb mixture onto each of the filled muffin cups.
Place muffin tin on a cookie sheet in case of overflow while baking. Bake in the preheat 350℉ for 20-25 minutes or until crumb topping is golden brown and the center of the muffin is firm to touch.