Preheat your oven to 350°F (175°C).

Line a muffin tin with paper liners or grease it lightly.

In a large bowl, mix together the dry ingredients: flour, oats, baking soda, baking powder, salt, cinnamon, and nutmeg.

In a separate bowl, whisk together the sugar, pumpkin puree, vegetable oil, and eggs until smooth.

Gradually add the wet mixture into the dry ingredients, stirring gently until just combined.

Fold in any optional ingredients, like nuts if desired.

Spoon the batter into prepared muffin tin, filling each cup about 2/3 full.

Bake in the preheated oven for 18-22 minutes, or until a toothpick inserted comes out clean.

Allow muffins to cool in the pan for 5 minutes before transferring to a wire rack.

Enjoy warm or at room temperature with your favorite spread or simply on their own!