In a large pot, add the stick of butter and melt over medium/high heat
Brown the butter by continuing to stir every 30 seconds or so and warming over medium heat. This will take about 5 minutes and the butter will be darker in color and smell “nuttier” when it is browned
Add in the marshmallows and melt over medium heat then turn off heat and add in extracts if using and cereal and mix well with spatula or large wooden spoon
Fold in sprinkles if desired then either add the crispy treats to an 9×12 baking dish (greased well) or into muffin tins!
Allow them to sit on counter to set for a bit then frost and enjoy