Set oven to warm, or to 150°F. After greasing a large bowl with butter, pour in the rice krispy cereal and place in the oven. The cereal will begin to warm while you start on the marshmallow fluff making it easier to mix later in this process!
180 g Chocolate Rice Krispies Cereal
In a small bowl, mix gelatin, 2 tablespoon water, and vanilla with a fork.
2 teaspoon Unflavored Gelatin Powder, 2 tablespoon Cool Water, 2 teaspoon Vanilla Extract
Combine the sugar, water, corn syrup, and salt in a pot. Turn on the stove to medium-high and heat until bubbling. Continue to cook without stirring until the mixture reaches 250°F.
60 g Water, 170 g Light Corn Syrup , 200 g Granulated Sugar , ½ teaspoon Salt
Pour the hot syrup into the bowl of your stand mixer and cool until your thermometer reads 212 degrees. Add the gelatin mixture into the sugar syrup and mix with the whisk attachment on low speed to combine. Once homogenous, increase the speed to medium-high and continue whisking until the syrup is thick and glossy. This should take 5-8 minutes.
Grease your 8x8 pan while you wait for the marshmallow fluff to finish mixing.
Add cocoa powder and softened butter to the marshmallow fluff and whisk to combine.
55 g Unsalted Butter, 30 g Black Cocoa Powder
Grab the warmed cereal from the oven and pour your chocolate marshmallow fluff into the bowl with the cereal. Using a spatula sprayed with oil, fold the cereal into the marshmallow fluff gently until combined.
Transfer the mixture into your prepared pan, gently pressing to the top of the rice krispie treats. Cover with plastic wrap and allow to rest and ingredients to cool/firm for 1-2 hours.