Unsalted butter (I usually brown up 3-4 sticks at a time).
Instructions
In a pan over medium-high heat, melt butter. Continue cooking, stirring frequently and adjusting temperature down if butter is splattering too much, until butter begins to brown on the bottom and becomes a golden brown color and smells nutty. This will take about 5 minutes or so. Remove from heat and let cool. If not using right away, store in the refrigerator until ready to use (up to 2 weeks) or freezer (up to two months).
Recipe by Wright Family Table at https://www.wrightfamilytable.com/brown-butter/