Duuuuude. These are so good. The recipe deviates from standard brownie prep in that you don't just melt the butter on the stove—you brown it before pouring it into the sugar. This recipe also uses cocoa rather than unsweetened baking chocolate (that cruelest of childhood lessons); I was afraid it would turn out too sweet, but nope—great.
Modifications: I added about a teaspoon of instant espresso powder with the cocoa. The recipe calls for half a cup of any kind of chocolate chips; I used Ghirardelli bittersweet, because I always have those around. (I would probably reduce the sugar in the batter if using a lighter chip.) Next time I want to try adding some warm spices (probably cinnamon, ginger, and cardamom), which I think would sing with the brown butter. This may become my new standard brownie.