Make this quickly in the same skillet you cooked fish in and serve it over the fish, or make it separately to use as a sauce for green vegetables.
Melt in a small skillet over medium-low heat:
Cook slowly until the butter becomes light brown and smells nutty, shaking the pan or stirring occasionally so it cooks evenly. Watch as the butter begins to foam; it can burn easily. When the foaming subsides a bit, swirl the pan. You should see browned bits on the bottom of the pan. Remove the butter from the heat. It can be used as is or season with:
Serve immediately.