1. Heat oven to 350 degrees . Toast walnuts for 10 minutes.
2. In bowl of a food processor, add walnuts, arugula, basil and garlic. Process 1 minute. Gradually add oil and process until fully incorporated. Add in cheese and salt and process until blended. Reserve 1/2 cup. Refrigerate remainder, covered, for another use for up to a week, or freeze for up to 3 months.Pasta and Shrimp:
3. Cook pasta following package directions, reserving 1/4 cup of the cooking water.
4. Season shrimp with salt and pepper. Heat olive oil in a large nonstick skillet. Saute shrimp for 2 minutes. Turn and saute an additional 2 minutes.
5. Toss drained pasta with the 1/2 cup reserved pesto and 1/4 cup of pasta water if necessary. Spoon into serving bowl and arrange shrimp on top. Makes 4 servings.