Preheat oven to 375 degrees and line a baking sheet with parchment paper.
With a stand, or handheld mixer, cream together the butter and sugars at medium speed until fluffy.
Add the eggs and vanilla and continue to mix until everything is combined.
In a medium bowl, whisk together the flour, baking soda, salt, cinnamon, and nutmeg.
Stir the quick oats into the dry ingredients.
With mixer running on low, add the dry ingredients to the wet ingredients in thirds and continue mixing, or mix by hand just until all ingredients are incorporated.
Drop balls of dough (2 Tablespoons for each ball) onto prepared baking sheet.
Bake for 8-10 minutes until slightly golden around the edges.
Allow cookies to cook for 3-5 minutes on pan, then transfer to a wire rack to finish cooling.
Creme filling:
With a stand or handheld mixer, beat the butter and confectioners sugar together until fluffy.
Add in the vanilla and salt, and beat for another minute until combined.
Gently fold in the marshmallow creme with a spatula or large spoon.