Add the first 10 ingredients to a food processor bowl and pulse until everything is consistent. Pour into the bowl of a mixer and add the molasses, egg, and milk.
Mix until everything comes together.
Line cookie pans with parchment paper.
Scoop cookie dough with a large cookie scoop and space at least 3-4 inches apart on the baking pan.
Bake for around 8 mins. and allow to rest on the pan for at least 5 mins. before removing to a wire cooling rack to finish cooling.
Add all Filling ingredients to a large mixer bowl. Using the whisk attachment mix until smooth.