Prepare Your Pan. Lightly grease a 9×13-inch baking pan and line it with parchment paper, leaving a bit of overhang on the sides to help lift the treats later. Set aside.

Brown the Butter. Place your butter in a large pot over medium-low heat. Allow it to melt completely, then continue cooking as it begins to foam and sizzle. Watch closely — you’ll notice golden specks forming at the bottom and a nutty aroma filling the air. When the butter turns a light golden-brown color, reduce the heat to low immediately. (If it darkens too quickly, remove it from the heat for a moment to cool.)

Melt the Marshmallows. Add 7½ cups (397 g) of mini marshmallows to the browned butter. Stir continuously with a silicone spatula until the marshmallows are almost completely melted. Be patient and resist the urge to increase the heat — keeping it low ensures the treats stay soft and chewy instead of hard.

Add Flavor. Stir in the vanilla extract and salt until everything is evenly combined and the marshmallows are fully melted into a smooth, glossy mixture.

Fold in the Cereal. Remove the pot from the heat. Immediately pour in the Rice Krispies cereal and fold gently until every piece is evenly coated in the marshmallow mixture. Work quickly before it starts to firm up.

Add Extra Marshmallows. Add the remaining 1 cup (53 g) of mini marshmallows and fold them through gently. These will soften slightly, creating delicious gooey pockets throughout the treats. Avoid overmixing — you want some texture left!

Transfer and Press. Pour the mixture into your prepared baking pan. Using a piece of parchment paper, wax paper, or plastic wrap as a barrier, lightly press the mixture into an even layer. Don’t press too firmly — a gentle hand keeps the texture soft and chewy.

Cool and Slice. Allow the treats to cool at room temperature for about 1 hour. Once set, lift them from the pan using the parchment overhang. Place on a cutting board and use a sharp knife to cut into even squares. Enjoy immediately!