Pumpkin~Apple streusel muffins { tried and true}

Ingredients:
2 1\2 c. flour
2 c. sugar
1 T. pumpkin pie spice
1 tsp. baking soda
1\2 tsp. salt
In large bowl, combine ingredients, set aside. In medium bowl,combine
2 eggs
1 c.pumpkin
1\2 c.vegetable oil
Stir well. Add to dry ingredients, stir just until moistened. Add: 
2 c. apples {about 2 medium-size apples} finely chopped
Stir well.Spoon batter into greased or paper lined muffin tins, filling 3\4 full.
In small bowl,combine { this is for streusel topping} 
2 T. flour
1\4 c. sugar
1\2 tsp. cinnamon
Cut in 4 tsp. butter until mixture is crumbly . Sprinkle on top of muffins. bake at 350  for 35 to 40 min., or until toothpick comes out clean. 
{ it says it makes 18, but we ended up making 23 good-sized muffins}