Preheat the oven and prepare the skillet:

• Preheat the oven to 350F. Lightly grease a 12” cast iron or oven-safe skillet with butter. Set aside.

Brown the butter:

• Add the butter to a saucepan over medium-high heat. Allow to melt and slightly brown (~5 minutes). Remove from the heat and immediately pour into a large bowl. Cool slightly.
• In a medium bowl whisk together the flour, baking soda, baking powder, and salt. Set aside.

Continue making cookie dough:

• Once the brown butter has cooled, add the avocado oil and both sugars, and whisk to combine.
• Add the eggs and whisk well until combined and lighter in color. Then, whisk in the heavy cream and vanilla.
• Add the dry ingredients to the wet, and fold until just combined.
• Fold in the chocolate chips/chopped milk chocolate and crushed graham crackers until evenly dispersed.

Assemble, bake, and serve:

• Transfer and press half of the cookie dough into the prepared skillet, making sure it is in an even layer. Arrange some of the graham cracker pieces all over the dough, and then add some of the marshmallows.
• Scoop the remaining cookie dough on top, and gently spread it over the marshmallows and graham crackers (it’s okay if the marshmallows aren’t covered).
• Press the remaining marshmallows and graham cracker pieces on top.
• Bake at 350F for 22-27 minutes, or until the edges are golden brown and the center has puffed yet is still slightly gooey in the middle.
• Remove and allow to cool for at least 10 minutes before serving.
• Serve the cookie skillet warm with a scoop of vanilla ice cream and sprinkle of flaky sea salt, if desired.

Enjoy!