Bring a large pot of water to a boil and salt generously (about 4 quarts of water, 2 tablespoons salt). Add pasta and cook according to the package instructions. With 2 minutes left, reserve about 1 cup of the pasta water before adding the veggies. Add in your asparagus and peas and boil for about 1-2 minutes. Drain and set aside.
In a high speed blender, add the soaked cashews, miso, lemon zest and juice, oil, salt, and ⅔ cup of the pasta water. Blend on high until totally smooth, scraping down the sides as needed (this will take about 1 minute).
Pour the sauce into the pasta pot (scrape up every last bit!) along with the pasta/veg and a few cranks of black pepper and toss to coat for about 1 minutes to let the pasta soak up the sauce. If it seems too thick, add a tablespoon more pasta water until it’s saucy. As the pasta sits, it soaks up the liquid, so it’s nice to have some extra pasta water on hand to thin it out. You could also just use regular hot water if you run out.
Serve topped with black pepper and herbs (if you’d like).