This sauce is also called buerre monté in classic French cooking.
It is best to use unsalted butter, as salt will come from the pasta water
- Add ¼ cup (60 ml) pasta cooking water to a skillet or saucier and bring to a lively simmer over medium-high heat. Let it bubble for a few moments.
- Reduce the heat to low. Add 4 tablespoons (55 grams) cold unsalted butter, 1 tablespoon at a time, and whisk or stir constantly until the butter melts and the sauce thickens.
- Add your cooked pasta and swirl the pan until it’s well coated.
- If the glaze gets too thick, add another splash of pasta water and swirl. If it separates, turn off the heat, add more butter, and swirl. And if you want to increase the amount of sauce, continue to add more pieces of butter.
- Serve immediately and drizzle more sauce on top.