Preheat the oven to 350°F and line a cookie sheet with parchment paper. Set aside.

In a stand mixer fit the paddle attachment, combine the butter, brown sugar, and molasses. Beat until light and fluffy, about 3 minutes.

Use a rubber spatula to scrape the sides of the bowl and add the egg and the vanilla extract. Mix well.

In a separate bowl stir together the flour, oats, baking soda, and salt.

Add the dry ingredients to the wet and mix until just combined.

Use 1 Tablespoon measure of a .5 ounce cookie scoop to scoop the dough out onto your cookie sheet 2 inches apart.

Bake 10 minutes or until the edges of the cookies are set and the centers have puffed up but are still underdone. Transfer the cookies to a wire rack. Allow the cookies to cool completely.

While the cookies cool, make the creme filling. Combine all of the ingredients in a stand mixer fit with the whisk attachment and beat on slow, gradually increasing to high until light and fluffy. Transfer to a piping bag fit with a round tip.

Pipe the creme filling onto the backside of one of the cookies and sandwich together with another cookie.

Store in an airtight container or ziploc bag for up to 7 days! Enjoy!