To make the rice krispie treats, add the butter to a large pot over medium heat. Whisk constantly until the butter is sizzling and brown bits
begin to form in the bottom of the pot, about 5 minutes. Turn the heat down to low and immediately add the marshmallows, stirring continuously with a wooden or heat safe spoon until melted. Stir in the vanilla extract. Turn off the heat and add the cereal, stirring until it’s all combined with the marshmallows. Press the mixture into an 8×8 baking dish and let it sit for 15 minutes.