1-First Step: Preheat and Prep Your Pan Start by preheating your oven to 350°F. Grease a 10-12 inch cast iron skillet with butter or non-stick spray. This prevents sticking and promotes even browning. Cast iron retains heat well, giving crispy edges and soft center. If using a smaller skillet, halve the recipe to avoid overflow.

2-Second Step: Cream Butter and Sugars In a large bowl, beat 1 cup softened unsalted butter, 1 cup brown sugar, and ½ cup granulated sugar until light and fluffy, about 2-3 minutes with a hand mixer. This incorporates air for tenderness. Scrape sides often. Room-temp butter mixes evenly, avoiding lumps.

3-Third Step: Add Eggs and Vanilla Beat in 2 large eggs one at a time, followed by 2 tsp vanilla extract. Mix until combined, about 1 minute. Eggs add moisture and help the cookie spread. If batter looks curdled, keep mixing; it smooths out.

4-Fourth Step: Mix Dry Ingredients In a separate bowl, whisk 2¼ cups all-purpose flour, 1 tsp baking soda, and ½ tsp salt. Stir in 1½ cups crushed graham crackers (pulse sheets in a food processor) and 1 cup semi-sweet chocolate chips. Gradually add dry mix to wet on low speed. Dough will be thick; fold by hand if needed for graham chunks.

5-Fifth Step: Press Dough into Skillet Transfer dough to prepared skillet. Use damp hands or a spatula to press evenly, about ¾-inch thick. Create slight edge for marshmallow containment. Bake at 350°F for 20 minutes until edges turn golden and center is set but soft.

6-Sixth Step: Add Toppings and Broil Remove from oven. Arrange 4-6 broken full-size chocolate bars over dough; they melt from residual heat. Scatter 2-3 cups mini marshmallows evenly. Switch to broil on high, 1-2 minutes until golden and puffed. Watch closely to prevent burning; rotate if needed.

7-Final Step: Cool and Serve Let rest 5-10 minutes for chocolate to set slightly. Serve warm with vanilla ice cream, spoons dug straight in. Pull-apart texture shines. Total time: 40 minutes. Inspired by classics like this skillet cookie version.