Step 1

Bring 8 cups water to a boil in a large pot. Cook pasta according to package instructions, adding peas during the last minute of cooking. Transfer 1/2 cup of the cooking water to a blender, then drain. Return the pasta and peas to the pot and cover to keep warm.

Step 2

Add arugula, goat cheese and pesto to the blender; process until smooth.

Step 3

Toss the pasta with the sauce, tomatoes and spring onions (or scallions). Serve warm or at room temperature, garnished with Parmesan and pine nuts, if desired.