Brown Butter Rice Krispie Treats

1 stick butter
1 10 oz bag small marshmallows
6 cups Rice Krispies
1/4 teaspoon kosher or sea salt (optional)

Melt the butter in a large saucepan, and brown over medium heat, stirring and being careful not to burn. Remove from heat, add marshmallows, and stir until marshmallows have melted. Add salt and Rice Krispies, stirring to coat. Press into a buttered 8x8 inch dish and let cool.

from http://smittenkitchen.com/2009/11/salted-brown-butter-crispy-treats/