Prep your pan. Line a 9x13-inch baking pan with parchment paper, leaving overhang for easy lifting. Lightly grease the parchment with nonstick spray or butter.
Measure the cereal. Add 8 cups of Golden Grahams to a large mixing bowl.
If you like bigger chunks, don’t crush them—keep the cereal whole for maximum crunch.
Reserve some marshmallows. Set aside 1–2 cups of mini marshmallows to stir in at the end. These keep the bars extra gooey and give visible marshmallow pockets.
Brown the butter for flavor. In a large pot over medium heat, melt 6 tablespoons of butter. Keep cooking, swirling occasionally, until it foams and the milk solids turn golden brown and smell nutty, 2–4 minutes. Don’t walk away—it can burn quickly.
Toast the marshmallows in the pot. Add 10 ounces of mini marshmallows to the browned butter.
Stir constantly over medium heat. Let a few bits caramelize slightly against the pan to build a toasted marshmallow flavor, but don’t scorch. When mostly smooth, turn off the heat.
Flavor boost. Stir in 1–2 tablespoons honey, 1 teaspoon vanilla, and a pinch of fine sea salt.
Taste and adjust the salt—just enough to sharpen the sweetness.
Combine gently. Pour the warm marshmallow mixture over the Golden Grahams. Use a greased spatula to fold until every piece is coated. Work quickly, but avoid crushing the cereal.
Add mix-ins. Let the mixture cool for about 1 minute, then fold in the reserved mini marshmallows.
If adding chocolate chips, wait another minute so they don’t fully melt—then fold them in for streaks and chunks.
Press into the pan. Transfer to the prepared pan. Lightly grease your hands or a piece of parchment and press the mixture into an even layer. Don’t compact it too hard or the bars will turn dense.
Optional flair. Sprinkle with flaky sea salt for contrast.
You can also scatter a few extra chocolate chips on top and gently press them in.
Set and slice. Let the pan sit at room temperature for 30–45 minutes to firm up. Lift out using the parchment overhang and slice into bars with a sharp, greased knife.