If you normally bake your cookies to be chewy, you want to be sure you bake your cookies a little longer than you normally would, as the filling makes them 'soft' and if they are too soft and chewy to begin with, they will fall apart. Start with a crisp cookie so it will be soft after the filling is added between them.
You have two options for the cookies; you can either use a round cookie cutter to cut them perfectly round, or use the cookies as they are - which is a nice round cookie anyway. Size is up to you as well. Larger, smaller, it doesn't matter. The size of your cookie is the size of your 'cookie sandwich'.
Chocolate Chip Cookies
Yield depends on the size of your cookies: about 7 regular size (14 cookies made into 7 creme sandwich cookies) or up to 18-20 mini if using a 1 1/2" round cookie cutter
1/2 cup butter
1 cup packed brown sugar
3 Tablespoons white sugar
1 large egg
1 teaspoon vanilla
2 cups flour
1/2 teaspoon baking soda
1/2 teaspoon baking powder
1/2 teaspoon salt
1 1/2 cup chocolate chips
Half of a 7 oz. jar Marshmallow Fluff (creme)
1/4 cup white, regular shortening
1/6 cup powdered sugar
1/2 teaspoon vanilla
dash of salt
In a bowl, with an electric mixer on medium speed, beat butter and sugars until well blended.
Beat in eggs and vanilla until smooth, scraping down sides of bowl as needed. In another bowl, mix flour, baking soda, powder, and salt. Stir or beat into butter mixture until well incorporated. Stir in chocolate chips.
Drop dough, 2 inches apart, onto baking sheets, (greased or on parchment paper). Bake in a 375° oven until cookies are lightly browned, about 10-12 minutes. Bake them about 1-2 minutes longer if you think they may still be too soft. Remember, the filling is going to make them very moist and soft after a couple hours. A crisp cookie is good to start with!
Make the filling while the cookies are baking by mixing all in a bowl with an electric mixer until fluffy. If it's a little dry, add just a teaspoon of warm water to it. You want it to be stiff and not runny though.
If you are using the cookies whole, remove them from the oven, let them set 2-3 minutes and then remove to cool completely. If you are cutting them into shapes or circles, use a cookie cutter and cut them out while still warm on the pan. If you want until they are completely cool they may crack or crumble if they are very crisp.
When completely cool, spread a bit of filling on the bottom of a cookie and sandwich it together with a second cookie. Let set at least an hour or two so the filling can soften the cookie. They will be perfect after about 6 hours if you can wait that long.
*if you 'cut out' your cookies you will have scraps. I save mine in a Ziploc in the freezer to crumble and use as a cheesecake base.