Use our Soft-Baked Oatmeal Cookie Mix as a base for this favorite skillet cookie.
Preheat the oven to 350 degrees (F).
Lightly grease an 8-inch cast-iron or another oven-proof pan
In a large bowl, stir together the cookie mix and melted butter or oil
Stir in the milk and eggs until combined
Fold in 1/2 the chocolate chips and 2 of the graham crackers
Pour the batter into the prepared pan and spread into an even layer
Sprinkle the marshmallows on top
Bake for 20-25 minutes. The marshmallows will brown slightly; be sure they don't begin to burn
Remove pan from the oven and sprinkle the remaining chocolate chips and graham crackers on top
Serve warm or allow to cool to room temperature
Store, covered, at room temperature for one day or in the fridge for up to 3 days