Preheat the oven to 325 F degrees.
In a large bowl, combine pumpkin puree, eggs, maple syrup, milk, and vanilla. Whisk together thoroughly.
Measure out 2 ½ cups of whole, old fashioned oats and blend them until very fine, like flour.
In a different bowl, combine blended oats, whole oats, baking powder, baking soda, and salt.
Mix the dry ingredients in with the wet ingredients and whisk thoroughly.
Mix in the optional ingredients, if desired.
Scoop batter into the muffin tins. Fill ¾ full.
Bake for 325 F degrees for 24-25 minutes. Check doneness with a toothpick. Should come out clean.