
Select your pan. For classic bars, use a 9x13-inch pan. For thick bars, use an 8x8-inch pan.
Grease your pan and line with parchment paper. Let the parchment paper overhang the edges to make it easy to lift the bars out of the pan.
Remove the pan from the heat. If you're using vanilla extract, stir it in now. Add the cereal and stir until coated.
Press the mixture evenly into your prepared pan. Tip: A piece of greased parchment paper makes this step easy.
Dairy-free option
Replace the butter with a dairy-free butter.