Cook fettuccine pasta according to package instructions. Reserve at least 1 cup of pasta water before draining the pasta.
Soak raw unsalted cashews overnight or soak them in almost boiling water for at least 15 minutes. Reserve soaking liquid.
Make the cashew cream sauce by adding soaked cashews, olive oil, the juice from one lemon, salt, and ½ cup reserved soaking liquid to a blender. Blend until smooth and creamy, adding extra liquid as needed to thin to a pourable consistency.
In a large bowl, toss the cashew cream with the cooked fettuccine and nutritional yeast. Add ½ cup pasta water back to the blender. Blend to remove any stuck-on cashew cream from the sides of the blender. Add to the cooked pasta.
To the pasta add sun-dried tomatoes, beans, peas, capers, the juice of one lemon, zest of one lemon (about 1 tablespoon), black pepper, and red pepper flakes to taste. Toss to combine.
Taste for seasonings. Enjoy immediately for a warm dish or cover and chill in the fridge for 2 hours for a cold dish.
Cashew cream: Soak time depends on blender strength. I soak mine in almost boiling water for just 15 minutes, but for a weak blender, you may need to soak them for 30 minutes. Cashews can also be soaked in cool water overnight. More tips can be found in my cashew cream post.
Leftovers: Enjoy leftovers hot or cold. Keep refrigerated in a closed container and enjoy within 3-4 days.
Even though I only use about ½ cup of pasta water in the sauce, I recommend reserving 1 cup in case you end up needing more.