01 - Cook the pasta according to package directions until al dente. Drain, reserving ½ cup of the cooking water, and set aside.
02 - While pasta cooks, combine soaked cashews, sun-dried tomatoes, plant-based milk, nutritional yeast, garlic, lemon juice, oregano, salt, and pepper in a high-speed blender. Blend until completely smooth and creamy.
03 - In a large skillet, heat olive oil (or reserved sun-dried tomato oil) over medium heat. Sauté chopped onion for 3–4 minutes until translucent.
04 - Pour the creamy sun-dried tomato sauce into the skillet and bring to a gentle simmer for 3–4 minutes, stirring occasionally.
05 - Add spinach and cook until wilted, about 2 minutes.
06 - Add cooked pasta to the skillet, tossing to combine. Add a splash of reserved pasta water if the sauce is too thick. Serve immediately, garnished with fresh basil and red pepper flakes if desired.