Prepare buttered 9x13 baking dish.

Melt butter on medium low in a heavy bottomed pot. Turn up the heat a little bit and cook butter until it becomes slightly browned and smells nutty.

Remove from heat and add marshmallows. Stir till fully melted.

Split vanilla bean lengthwise down the middle and carefully scrape out seeds and add to marshmallow mixture. Stir to evenly distribute flecks.

Stir in cereal and transfer immediately to buttered baking dish. Gently press even with wax paper or wet fingers to prevent sticking. Do not press hard, just enough so the treats are evenly distributed. You want them to stay light!

Cool completely and cut into squares.