Fill a large pot with water, add a generous pinch of salt, and bring it to a rolling boil. Cook the pasta according to package directions until al dente. Before draining, scoop out and reserve 1/2 cup of the pasta cooking water. Drain the pasta and set it aside.

In a high-speed blender, combine the soaked cashews, sun-dried tomatoes with a little of their oil, 1/2 cup water, garlic, and lemon juice. Blend on high until completely smooth and creamy. If the mixture feels too thick, add more water one tablespoon at a time until you reach the sauce texture you want.

Taste the sauce and add salt and freshly ground black pepper to your preference. Adjust lemon if you want more brightness.

Warm a large skillet over medium heat. Add the drained pasta, then pour in the creamy sauce. Toss constantly for 1 to 2 minutes so the pasta heats through and the sauce loosens. Add a splash of the reserved pasta water if needed to help the sauce coat the pasta evenly.

Serve immediately on warmed plates and top with torn fresh basil, a sprinkle of vegan parmesan, and red pepper flakes for a little heat.