Browned Butter-Pecan Chewy Crispy Bars

Melt butter over medium-low heat; cook melted butter 3 minutes or until browned. Add marshmallows; stir and cook until melted. Add kosher salt and vanilla to melted marshmallows; stir well. Add cereal; toss well to combine. Press into a 13 x 9-inch pan coated with cooking spray; sprinkle evenly with pecans.