Bring a large pot of salted water to a boil. Add the rigatoni pasta and cook according to package instructions until al dente, about 10-12 minutes. Drain and set aside.
While the pasta cooks, heat olive oil in a large skillet over medium heat. Add the sliced vegan sausage and cook for 5-7 minutes, turning occasionally, until browned and slightly crispy. Remove the sausage from the skillet and set aside.
In the same skillet, add the chopped onion and cook for 4-5 minutes until softened and translucent. Add the minced garlic and cook for 1 minute until fragrant.
Meanwhile, prepare the cashew cream sauce by blending the soaked cashews, water, nutritional yeast, lemon juice, smoked paprika, dried oregano, salt, and black pepper in a high-speed blender until completely smooth and creamy.
Pour the cashew cream sauce into the skillet with the onions and garlic. Stir well and cook over medium heat for 3-4 minutes until the sauce thickens slightly.
Add the cooked rigatoni pasta, browned vegan sausage, and chopped baby spinach to the skillet. Stir gently to combine and cook for another 2-3 minutes until the spinach wilts and everything is heated through.
Remove from heat and stir in the chopped fresh parsley. Adjust seasoning with additional salt and pepper if needed.
Serve the creamy vegan sausage pasta skillet hot, garnished with extra parsley if desired.