And it really is as simple as putting the butter in the microwave and pressing "On." Tosi says to put the butter in a microwave-safe bowl and cover it with another microwave-safe bowl or plate to avoid splattering your microwave with hot butter. Microwave for 3-5 minutes, depending on how much butter you're melting down.
Tosi says, "The butter will melt, then start to pop and begin to brown during this period." She also says not to be afraid to let it get really dark brown. "You want it deep brown in color and super-nutty in aroma." Yes. Yes, we do.
My only fear with this method is that it now makes browning butter far too easy. Without the fuss of making it on the stove top, what's to stop me from browning a few pats for my morning oatmeal or midnight snack of popcorn? This could be trouble.
Related: Techniques: How to Brown Butter