Steps
1. Preheat oven to 375°F (190°C) and line a muffin tin with paper liners.
2. In a small bowl, combine 1/2 cup flour, 1/4 cup sugar, baking powder, and salt. In another bowl, whisk together milk, vegetable oil, and vanilla extract. Combine wet and dry ingredients, then gently fold in blueberries.
3. For the crumb topping, mix 1/4 cup flour and 2 tbsp sugar. Cut in cold butter until crumbly.
4. Fill muffin cups with batter, sprinkle crumb topping over each muffin.
5. Bake for 20-25 minutes until a toothpick inserted comes out clean.
6. Let cool slightly before enjoying!