You may never want a "normal" sized cookie again!
In the bowl of a stand mixer (or using a hand-held mixer on the highest setting) cream together butter and sugar (about 2-3 minutes).
With the mixer on low (or off) add in the flour, baking soda, and salt. Then add in the lemon juice. Mix until just combined.
Using a 1/2 cup measuring cup, scoop out the dough and form into rounded balls with your hands, then press down slightly to form a disc shape.
Mix the 3 tablespoons sugar and the cinnamon in a wide bowl. I like to use a fork but a small whisk also works.
Roll the dough in mixture. Place 2 cookies at least a few inches apart on a parchment-lined baking sheet.
Bake 14-16 minutes. Cookies should puff up a bit and then fall slightly after cooling.
Add confectioners sugar, cream cheese, marshmallow fluff, and cinnamon to a large bowl or the bowl of a stand mixer. Mix on medium speed for about 3 minutes, or until the frosting is smooth and creamy. (It will start out very thick, continue mixing until it is creamy.)
Take one large cookie and place about 1/4 cup of frosting. Smooth with an offset spatula.
Drizzle with 1 tablespoon of caramel sauce.
Place a cookie on top and press down slightly. Repeat with the rest of the ingredients to make 3 total sandwich cookies. (You may have one remaining individual cookie.)