Gooey S'mores Cookie Skillet

0 Preheat your oven to 350F degrees.
1 In the microwave or on the stovetop, melt the butter and then let cool completely.
2 In a large mixing bowl, whisk together butter and sugar until it's smooth and incorporated.
3 Add in the eggs and vanilla extract and mix until combined.
4 Next, add in the flour, sea salt, and baking soda. Mix until everything is well combined.
5 Pour in the chocolate chips, marshmallows, and crumbled graham crackers (reserve some of each for topping if you'd like) and using a spatula, mix until well distributed. The batter should be thick & sticky,
6 Coat a 10in cast iron skillet with oil or butter. If you don't have a cast iron you can always use cake pan!
7 Press dough into the skillet and bring it all the way to the edges. If the batter is too sticky, lightly wet your hands to help press it into the pan without sticking to you.
8 Bake in the oven for 30-40 minutes. If you want it more gooey, lean toward the shorter time. If you'd like it a little more done, go longer. Check at 25-30 minutes. 
9 Top with flakey sea salt. To cut into slices, let cool completely before slicing. To enjoy hot, eat it right from the skillet with a spoon. Enjoy!