Bring a large pot of water to a boil; add 1 teaspoon salt. Add peas, and cook until tender, 3 to 4 minutes. Using a slotted spoon, transfer peas to a small bowl and set aside.
Bring another large pot of water to a boil; add 1 teaspoon salt. Add pasta and cook per package directions. Drain and set aside.
Meanwhile, to make the pesto, combine basil, garlic, cheese, walnuts, and lemon juice in the bowl of a food processor fitted with a blade attachment. Pulse several times until finely chopped. With the machine running, slowly add the olive oil in a steady stream. Season to taste with salt and pepper.
In a large bowl, combine pasta, peas, and pesto; stir to incorporate. Season to taste with salt, pepper, and more lemon juice. Garnish with additional basil and walnuts (optional).
Beth Blessing (Organic Beth) has a Masters in Nutrition and is the co-founder of Green BEAN Delivery. She is a mother of two that loves supporting family farms and searching for unique, artisanal products. Her goal is to help others eat better and live a more natural, holistic life through healthy recipes and practical tips. Follow her at facebook.com/organicbeth