http://www.food.com/recipe/basil-walnut-pesto-45348
Place basil, olive oil, walnuts, garlic and salt (if using) in food processor.
Blend until thoroughly combined.
Add Parmesan and butter (if using) and blend 5-10 seconds more.
Just before serving, add 2 Tbsp of hot pasta water from cooked pasta.
Serve over pasta with bread and salad.
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