Line a 9x13-inch baking dish with aluminum foil and lightly coat with nonstick spray. Set aside.

In a large pot over medium heat, melt the butter. Stir in the vanilla extract and salt.

Add 10 oz of the mini marshmallows to the pot and stir continuously until completely melted and smooth. Remove from heat.

Quickly stir in the rice cereal, crushed graham crackers, and the remaining 5 oz of mini marshmallows. Gently fold in about ⅔ cup of the chopped chocolate or chocolate chips. The heat will create a delicious swirl effect.

Transfer the mixture to the prepared baking dish. Using a spatula, gently press it down into an even layer. Let sit for at least 15 minutes to cool and set.

Remove the treats from the pan and set on a cutting board or clean surface.

In a microwave-safe bowl, melt the remaining chocolate in 15 to 20 second intervals, stirring until smooth.

Drizzle the melted chocolate over the top and sprinkle with extra marshmallows and crushed graham crackers. Let the chocolate harden.

Optional: Toast the marshmallows on top using a kitchen torch for that classic s’mores flavor.

Cut into squares and enjoy!