Butter a 9x13 pan and set aside.

In a large kettle, melt butter over medium heat, whisking occasionally. The butter will start to foam and then begin to brown after 3-4 minutes. When you smell the nutty butter flavor and it has turned an even brown color, add your marshmallows and lower the heat to low.

Stir the marshmallows vigorously until they are melted and smooth. Stir in the vanilla extract.

Fold the toasted rice cereal into the melted marshmallows until everything is well combined.

Using buttered hands, press the mixture into the greased pan.

Cool in the refrigerator before cutting for clean square cuts. Store in an airtight container for up to 3 days. If storing in layers, place parchment paper between each layer.