When sauce simmers, whisk in remaining 2 tablespoons butter.

While the sauce simmers, bring a pot of salted water to a boil.

After sauce has simmered for 15 minutes, remove 1 cup and set aside to cool.

Place pan over low heat so that sauce just barely simmers.

He is the kind of weekend chef who makes sauces from stock reductions involving beef bones roasted then simmered for hours on end.

After the sauce simmered for a few minutes, he strained out the vegetables and whisked in butter with a handheld blender.

While the sauce simmered in the twenty-first-century pot, she carried the ancient kettle to the sink to wash it.

While the sauce simmers, heat the water for the pasta.

The dark green sauce simmers on low heat and is left to thicken to the consistency of tomato sauce.

The sauce, which also includes garlic, onions, tomatoes, chicken broth and bay leaf, simmers for only 10 minutes.