Creating your own Apple Pumpkin Streusel Muffins is a simple yet rewarding process. Just follow these easy steps:

1. Preheat the Oven: Preheat your oven to 350°F (175°C). Line a muffin tin with paper liners or grease it lightly.

2. Prepare the Muffin Batter: In a large mixing bowl, combine the flour, baking powder, baking soda, salt, and pumpkin pie spice. Mix well and set aside.

3. Mix Wet Ingredients: In another bowl, whisk together the pumpkin puree, grated apple, granulated sugar, brown sugar, vegetable oil, eggs, and vanilla extract until thoroughly combined.

4. Combine Mixtures: Gradually fold the dry ingredients into the wet mixture. Stir until just combined; do not overmix. It’s okay if some lumps remain.

5. Add Optional Ingredients: If you’re using nuts, fold them gently into the batter.

6. Make the Streusel Topping: In a separate small bowl, mix together the flour, rolled oats, brown sugar, cinnamon, and softened butter. Use a fork or your fingers to blend until crumbly.

7. Fill Muffin Tin: Divide the muffin batter evenly into the prepared muffin tin, filling each cup about ¾ full.

8. Add Streusel: Sprinkle the streusel topping generously over the muffin batter in each cup.

9. Bake: Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted in the center comes out clean.

10. Cool: Allow the muffins to cool in the pan for about 10 minutes before transferring them to a wire rack to cool completely.