Preheat the oven to 350° and line two cookie sheets with parchment paper.
Cream together the butter, sugars, molasses, vanilla extract, and eggs until light and fluffy. Then mix in the baking soda, salt, and flour, until a soft dough forms. Then mix in the oats until evenly distributed.
Using a 2 tbsp cookie scoop, scoop the cookie dough onto the cookie trays (8 to a pan usually works fine) and bake for 12-14 minutes and press down with a spatula fresh out of the oven. The edges will be browned and the middle with still be soft and pressing them down maintains that chewy center as they cool. Then allow to cool.
Cream together the butter, shortening, and marshmallow cream until fluffy. Then mix in the powdered sugar and vanilla as needed. It should be light and fluffy, it should be thick but not so thick that you can’t pipe it.
Pipe into the middle of the cookies (however much you want) and bone apple teet! Hope y’all enjoy!