Melt the butter: Place butter in a medium skillet over medium heat and let it melt slowly.
Brown the butter: Stir occasionally until the butter turns golden brown and smells nutty (about 4–5 minutes).
Add the sage: Toss in fresh sage leaves; let them crisp up in the butter for 30–60 seconds.
Season: Add a pinch of salt and, if using, a splash of lemon juice to brighten the flavor.
Serve: Pour over pasta, gnocchi, roasted vegetables, or meat. Sprinkle with grated Parmesan if desired. Serve immediately.
