Melt butter in light-colored pan over medium heat. Cook swirling gently until foam subsides and milk solids turn golden and smell nutty — 2–3 minutes. Remove from heat immediately.
Return to low heat. Add fresh sage leaves, swirl to coat, crisp 20–30 seconds until bright and slightly darker at edges.
Add reserved pasta water carefully — it will bubble. Swirl and stir to emulsify into glossy unified sauce. Season with salt and pepper.
Add freshly cooked ravioli directly to pan, toss gently to coat. Finish with freshly grated parmesan and pinch of nutmeg. Serve immediately on warm plates.
Notes
- Use a light-colored pan — you must see the butter color change to avoid burning. - Have everything ready before starting — brown butter moves fast. - Serve immediately on warm plates — the sauce solidifies quickly as it cools.
Keyword brown butter sage sauce, sage butter pasta sauce, easy ravioli sauce