In a large mixing bowl, beat together 1 cup of softened unsalted butter with 1 cup of brown sugar and 1/2 cup of granulated sugar until the mixture is creamy and smooth.

Add in the molasses and vanilla extract. Mix well, then incorporate the eggs, one at a time, ensuring each is fully incorporated before adding the next.

In a separate bowl, whisk together the all-purpose flour, cinnamon, baking soda, and salt until well combined.

Gradually add the dry ingredients to the wet mixture. Once combined, fold in the quick oats gently until everything is just mixed; avoid overmixing to maintain a tender cookie.

Preheat your oven to 350°F (175°C). Using a cookie scoop or spoon, drop portions of dough onto lined baking sheets, ensuring they are spaced apart as they will spread while baking.

Bake in the preheated oven for 10-12 minutes or until the edges are golden brown, and the centers appear soft but set. Remove them from the oven and let them cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely.

In a mixing bowl, beat the remaining softened butter with cream cheese until smooth.

Gradually add powdered sugar until you reach your desired sweetness, then mix in the vanilla and salt until fully incorporated. If the filling is too thick, add a tablespoon of cream to loosen it.

Once the cookies have cooled, spread the cream filling on the flat side of half of the cookies and top with the remaining cookies to create a sandwich.