As much sliced, unsalted butter as your recipe calls for. Slice butter evenly for even cooking time.
Place butter in a small saucepan over medium heat and immediately begin whisking. Stir as it foams up, and after 2-3 minutes or so you should see brown bits appear on the bottom of the pan. Remove from heat immediately and continue to whisk for another 30 seconds. It’s pretty easy to overcook browned butter and go from brown to burnt. If the butter starts to blacken, I suggest dumping it and starting over. Use as desired!