In a large saucepan or dutch oven, melt the butter over medium heat.
Add the mini marshmallows to the melted butter and stir until completely melted and smooth.
Remove the saucepan from heat and stir in the chocolate chips until melted and well combined.
Pour the Rice Krispies cereal into the saucepan and gently fold until evenly coated with the chocolate mixture.
Transfer the mixture into the prepared baking dish and press it down evenly with a spatula.
Allow the Chocolate Rice Krispies to cool and set at room temperature for about 30 minutes.
Once set, cut into squares and serve. Enjoy your chocolate crunchy treat!
Notes
Melt the marshmallows over medium heat, stirring constantly. Overheating can cause them to become too stiff, making it harder to mix with the Rice Krispies.
Once the marshmallows and chocolate are melted and mixed, work quickly to combine with the Rice Krispies. The mixture can set fast, making it more difficult to spread evenly in the pan.
For clean, neat squares, make sure to let the treats cool completely at room temperature before cutting them into squares.