Place the butter, almond butter, seeds from the vanilla beans and chocolate chips in a large heatproof bowl set over a pan of barely simmering water. Stir till completely melted. Add the cereal and stir gently but thoroughly till well coated.

Pour mixture into a large ziploc bag, add the confectioner's sugar and shake to coat. Place in a single layer on a foil-lined baking sheet, and let cool. Try to gather the cereal on the sheet in a single layer with as few gaps between the pieces as possible.

Sprinkle with the granulated sugar and either broil or use a torch to caramelize the tops. Let harden, then cover with another piece of foil, followed by a second baking sheet and carefully invert so that the bottoms are now facing upward. Sprinkle with granulated sugar and broil or torch. Let harden and store in an airtight container.