“Beurre Noisette” is French for “brown butter,” and it provides a delicate nuttiness that really makes the Brussels sprouts pop.
Halve about 10 small Brussels sprouts per person (they needn’t be tiny, but you don’t want giant ones) and drop into boiling, salted water. Boil for about 3 minutes, until bright green and slightly less tender than you want to eat them. Drain and set aside.
Place a tablespoon or so of butter into a light-colored pan. Don’t use nonstick – the color is too dark to judge the doneness of the butter, and sticking isn’t an issue here. Melt over medium-low heat, then continue cooking, swirling the pan occasionally, for a few more minutes, until the butter is brown. The browner you get it, the more flavorful it will be, but the greater your risk of burning it.
When the butter is done to your liking, remove from the heat and immediately add the Brussels sprouts, swirling the pan to coat the sprouts with the butter. Add salt, pepper, and lemon juice to taste and serve immediately.