Muffins:

• 1 ½ cups all-purpose flour
• ¾ cup white sugar
• 2 teaspoons baking powder
• ½ teaspoon salt
• ⅓ cup vegetable oil
• 1 egg
• ⅓ cup milk, or more as needed
• 1 cup fresh blueberries

Crumb Topping:

• ½ cup white sugar
• ⅓ cup all-purpose flour
• ¼ cup butter, cubed
• 1 ½ teaspoons ground cinnamon

2. Preheat the oven to 400 degrees F (200 degrees C). Grease 8 muffin cups or line with paper liners.
3. For the muffins: Whisk flour, sugar, baking powder, and salt together in a large bowl.
4. Pour oil into a small liquid measuring cup. Add egg and enough milk to reach the 1-cup mark; stir until combined. Pour into flour mixture and mix just until batter is combined. Fold in blueberries; set batter aside.
5. For the crumb topping: Combine sugar, flour, butter, and cinnamon in a small bowl. Mix with a fork until crumbly.
6. Spoon batter into the prepared muffin cups, filling right to the top. Sprinkle with crumb topping.
7. Bake in the preheated oven until a toothpick inserted in the center of a muffin comes out clean, 20 to 25 minutes.