Preheat Oven to 350F. Line two baking trays with parchment paper.
In a large bowl, Add flour, Oats, Baking Soda, Cinnamon, and Salt.
Beat butter and sugars, and molasses until very fluffy and pale in color. Add in eggs, and Vanilla until well combined.
Add the dried ingredients, mix until just combined.
Scoop about 1 1/2 tablespoons each cookie, you should get about 16 cookies (8 oatmeal cream pies)
Bake 350 for 9-10 minutes. Do not overbake!
While the cookies are baking, Start on the Cream Filling. Beat Room temp butter and Confectioners Sugar until all lumps are out. Slowly add in heavy cream, pinch of salt, Vanilla extract and marshmallow fluff. Beat low and slow until smooth.
Pipe a generous amount of cream between 2 cookies and Enjoy!