Line 2 large baking sheets with parchment paper. Set aside.
Prepare your s’mores filling ingredients by cutting your marshmallows in half, breaking your graham crackers into smaller pieces (break the larger cracker into the rectangles and then break those rectangles in half) and do the same with your chocolate bars. Set aside. Note: These ingredients will be divided between 12 cookies.
In a large mixing bowl with a hand held mixer or the bowl of a stand mixer, beat the butter and both sugars until creamy. Add the eggs, one at a time and the vanilla extract. Beat mixture until well combined and fluffy.
In another large bowl combine the flour, baking soda, and salt. Whisk together.
Slowly add the dry ingredients to the butter mixture. Beat together until well combined, being careful not to overmix it.
Using a large spatula, add the chocolate chips and gently fold them into the dough.
Using a 3 tablespoon cookie scoop, scoop out 24 cookie dough balls. Divide those between the 2 prepared baking sheets (12 cookies per sheet). Gently flatten each dough ball into a 3 inch disc.
On only 12 of your cookie discs, you will place 1 half of a marshmallow, a couple pieces of broken graham cracker and a couple pieces of broken chocolate bar. Be careful not to overstuff your cookies.
Gently place the remaining cookie dough discs on top of the others. Gently press the edges together, then roll them around in your hands to create a jumbo cookie ball.
Once you have finished making all your stuffed s’mores cookie balls, place them on just 1 of your prepared cookie sheets and place that cookie sheet into your freezer (being careful that it remains flat) for 30 minutes.
While your cookies are in the freezer Preheat your oven to 375 degrees F.
Depending on the size of your baking sheets, place 4 to 6 frozen cookie balls onto your parchment lined baking sheets. Pro Tip: Be sure to leave plenty of space between cookies. These cookies will be very large once baked.
Bake your cookies for 13 to 15 minutes or until lightly golden on the edges and the centers are just set. Repeat with your next batch.
Allow your cookies to cool on the tray for 3 to 4 minutes before enjoying them. Remember that gooey marshmallow inside will be very hot.