Boil your pasta in salted water according to package directions until a dente. (It will cook a little bit more in the sauce at the end.)
Peel and dice an onion into small pieces. Sauté it in a large skillet with 2 tablespoons of olive oil and 1/2 teaspoon of salt over low heat for 5 minutes.
Add minced garlic and sauté for another minute, then add the fresh or frozen peas to the onions and garlic and turn the heat to medium.
Scoop out 1 cup of pasta cooking water and add it to the skillet with the peas with 4 tablespoons of butter and simmer for about 5 more minutes until the butter is melted and the peas are tender.
Add 3/4 cup of vegan parm (saving 1/4 cup for garnishing) and give it a good stir and allow the cheese to melt.
Drain the cooked pasta, then add it to the cooked peas. Stir well and add salt and pepper to taste and a few shakes of red pepper flakes if desired. Allow it to sit for a few minutes to soak up the flavors of the sauce.
Sprinkle with fresh chopped parsley and the remaining 1/4 cup of vegan parm.
Notes
Saute the onion over low heat to bring more sweetness and flavor.
To make this a creamy pea pasta sauce - Transfer the cooked onion and pea mixture to a blender and puree it until smooth before mixing it with the pasta. You can add a little pasta water until the desired consistency is achieved. (This is great for kids and picky eaters.)
Don't want to use butter? You can swap it out for 1/2 cup of cashew cream or coconut cream.