Fill a large pot with a few inches of water and fit it with a steamer basket. Bring the water to a boil, then lower it to a simmer. Place the asparagus in the basket and steam for 3-4 minutes, or until bright green and tender. Remove the asparagus from the basket and transfer it to a colander or bowl for holding. Add the sugar snap peas to the steamer basket. Steam the snap peas for 2 minutes, or until bright green and crisp tender. Remove the peas and add them to the colander with the asparagus. Finally, add the peas to the steamer basket. Steam for 1-2 minutes, or until the peas are bright green and tender, then transfer them to the colander or bowl with the other vegetables. Set the vegetables aside.
Fill the pot with enough additional water to boil pasta. Salt the water and bring it to a boil. Add the pasta and cook according to package instructions, or until cooked through but still slightly al dente (or to your liking). Drain the pasta, reserving 3/4 cup of the cooking water.
In the meantime, heat the olive oil on medium low heat in a large, deep skillet. Add the shallots. Cook for 1 1/2-2 minutes, stirring constantly, or until the shallots are clear and tender. Add the garlic. Cook for another minute, stirring constantly, or until the garlic is very fragrant. Add the the pasta to the skillet, along with 6 tablespoons of the pasta cooking water. Add 4 tablespoons of cashew sour cream or all-purpose cashew cream, lemon zest, lemon juice, and salt to the skillet and stir to coat the pasta well.
Add the steamed vegetables. Fold everything together gently, heating the ingredients as you go. Add an additional couple tablespoons of the cooking water or cashew cream to loosen the pasta as needed; you’re aiming for a creamy, yet light, sauce. Add freshly ground pepper and additional salt or lemon juice as needed.
Serve the pasta right away, garnished with fresh chopped herbs or cashew parmesan, or store for up to 4 days in an airtight container in the fridge. The pasta can also be frozen for up to 4 weeks.