Add the soymilk, cashews, nutritional yeast, mustard, salt, pepper, garlic, lemon juice, tahini and smoked paprika into the bowl of a food processor or blender and process until smooth and creamy. Set aside

Cook pasta following packet instructions. Drain pasta, reserving 1 cup of the cooking water

In a fry pan on high heat, add the oil and onion and cook until transparent. Add sliced mushrooms and cook until they have softened. Pour in the alfredo sauce and stir until heated through

Transfer cooked pasta and 1/2 cup of the hot starchy water to the pan. Use as much of the cooking water to help to thin out the sauce. Add the baby spinach and stir until the sauce has heated through and the baby spinach has wilted. Serve immediately with extra salt and pepper