2 1/2 cups all-purpose flour
2 cups white sugar
1 tablespoon pumpkin pie spice
1 teaspoon baking soda
1/2 teaspoon salt
2 eggs, lightly beaten
1 cup canned pumpkin puree
1/2 cup vegetable oil
2 cups peeled, cored and chopped apple
2 tablespoons all-purpose flour
1/4 cup white sugar
1/2 teaspoon ground cinnamon
4 teaspoons butter
Preheat oven to 350 degrees F (175 degrees C). Lightly grease 18 muffin cups or use paper liners.
In a large bowl, sift together 2 1/2 cups all-purpose flour, 2 cups sugar, pumpkin pie spice, baking soda and salt. In a separate bowl, mix together eggs, pumpkin and oil. Add pumpkin mixture to flour mixture; stirring just to moisten. Fold in apples. Spoon batter into prepared muffin cups.
In a small bowl, mix together 2 tablespoons flour, 1/4 cup sugar and 1/2 teaspoon cinnamon. Cut in butter until mixture resembles coarse crumbs. Sprinkle topping evenly over muffin batter.
Bake in preheated oven for 35 to 40 minutes, or until a toothpick inserted into a muffin comes out clean.