Step 1: Prep

1. Preheat the oven to 325°F (165°C).

2. Line a baking sheet with parchment paper and set aside.

3. Tip: Use a light-colored baking sheet to prevent over-browning, and ensure parchment paper is flat for even baking.

Step 2: Brown the Butter

1. In a small saucepan, melt 150 g unsalted butter over medium heat, stirring occasionally.

2. Cook for 13–15 minutes until the milk solids separate, turn golden brown, and the butter smells nutty. Watch closely to avoid burning.

3. Pour 125 g of the browned butter into a large mixing bowl and let cool for 10–15 minutes.

4. Tip: Use a light-colored pan to monitor the butter’s color, and swirl the pan occasionally for even browning.

Step 3: Prepare the Dry Mixture

1. In a small bowl, stir together 180 g all-purpose flour, ½ teaspoon baking powder, ½ teaspoon baking soda, and ½ teaspoon salt.

2. Set aside.

3. Tip: Whisk the dry ingredients to ensure even distribution of leavening agents.

Step 4: Make the Wet Mixture

1. Add 150 g brown sugar to the cooled browned butter and whisk until combined.

2. Add 1 large egg (room temperature) and 2 teaspoons vanilla extract, whisking for about 3 minutes until the mixture is light brown and smooth.

3. Tip: Ensure the butter is cooled to prevent scrambling the egg, and whisk vigorously for a cohesive mixture.

Step 5: Combine Wet and Dry Mixtures

1. Add the dry mixture to the wet mixture and fold with a spatula until semi-incorporated, with some flour patches remaining.

2. Add 50 g roughly crushed graham crackers and 100 g chopped dark chocolate, folding until just incorporated and no dry flour patches remain. Avoid overmixing.

3. Tip: Crush graham crackers by hand for varied texture, and fold gently to keep the dough tender.

Step 6: Scoop and Top

1. Use a 4-tablespoon cookie scoop to portion the dough into balls, placing them on the lined baking sheet with about 2 inches of space between each for spreading.

2. Firmly press 1 large marshmallow into the top of each dough ball, creating an indentation to hold it in place.

3. Tip: If marshmallows are large, cut them in half for easier placement and even toasting.

Step 7: Bake

1. Bake at 325°F (165°C) for 9–10 minutes, until the marshmallows are puffy and lightly browned but the cookies remain soft.

2. Remove from the oven and, if desired, use a fork to gently push in uneven edges or swirl each cookie inside a large round cutter for perfectly round shapes.

3. Let cookies cool on the baking sheet for at least 5 minutes before transferring to a wire rack to cool completely or enjoy warm.

4. Tip: For extra-toasty marshmallows, briefly broil the cookies for 30–60 seconds after baking, watching closely to avoid burning.