Place the butter in a small or medium light-colored saucepan on the stove over medium-low heat. Stir with a rubber spatula as the butter begins to melt. Note: Make sure you are always stirring throughout this process!
1 stick unsalted butter
The butter will begin to foam on top and sizzle. Make sure you continue stirring! After 5-7 minutes, you'll start to see milk solids at the bottom of the pan. When you stir and the foam moves, you'll be able to see those milk solids.
At this point, the sizzling should have stopped, but you might still have some foam on top (although it should be subsiding by now!). The milk solids at the bottom should turn golden brown and the butter should smell nutty and toasted.
Turn off the stove and pour the browned butter into a heatproof bowl. Make sure you use the rubber spatula to scrape out all the brown bits into the bowl. Let cool and use as desired.
Video
Notes
Make Ahead: Depending on your recipe, you might want to make this ahead of time! If the butter in your recipe needs to be at room temperature, let the brown butter cool in the bowl and then place it in the fridge until firm enough. Amount of Butter: I've used a stick of butter as an example here, but use however much butter your recipe calls for!