Apple Cinnamon Muffins

Ingredients
1 1/2 cups all purpose flour
1/2 cup granulated white sugar
1/2 cup packed brown sugar
2 teaspoons baking powder
2 teaspoons ground cinnamon
1/2 teaspoon salt
1/3 cup vegetable or canola oil
1 large egg
1/3 cup milk
1 large apple (peeled, cored & chopped)
TOPPING:
1/4 cup granulated white sugar
2 tablespoons all purpose flour
2 tablespoons butter, at room temperature
1 teaspoon ground cinnamon
Instructions
Preheat oven to 400°F. Grease a 12-cup muffin tin or line with paper muffin liners.
In a medium bowl whisk together dry ingredients. Add oil, egg and milk and stir just until combined. Fold in apples. Divide batter between the 12 muffin cups.
In a small bowl, mix topping ingredients, blending together with a pastry cutter or fork. Sprinkle over unbaked muffins.
Bake 15 to 20 minutes, or until a toothpick inserted in center of muffin comes out clean.