Salted Brown Butter Rice Krispy Treats

1 cube butter plus extra for buttering the pan
10 oz. marshmallows
1/4 teaspoon coarse sea salt
6 cups Rice Krispies cereal
Butter a square cake pan.

In a large pot melt butter over medium low heat.  It will melt, then
foam, then turn clear golden and finally start to turn brown and smell
nutty.  Stir constantly scraping up any bits from the bottom.  Don't
take your eyes off the pot as it will go from a little color to burned in
less than a minute.

As soon as the butter takes on a nutty color, turn off the heat and stir
in the marshmallows.  The residual heat from the melted butter should
be enough to melt them but if it is not, turn it back on low until the
marshmallows are smooth.

Remove the pot from the stove and stir in the salt and cereal. Quickly
spread into prepared pan.  A piece of waxed paper or a silicon spatula
will help you to spread Rice Krispy treats evenly into the corners.
Cool and cut into squares.