Prepare ravioli according to package directions. Drain and set aside.
For the Pesto Alfredo
To a small pot, add cashews and enough water to cover 1". Bring to a boil for 8 minutes. Drain and set aside. Do not return to pot yet.
To a medium skillet over medium high heat, add olive oil. When oil is hot, add onions. Cook, stirring frequently, 3 minutes, until softened, Add garlic and cook anaditional 1 minute. Remove from heat.
Into a high speed blender, add water, cashews, lemon juice, salt, and pepper.
Puree on high 2-3 minutes, until consistency is very smooth.
Into the pot used to cook ravioli, pour in the alfredo sauce. Turn heat to low then add spinach, parmesan, mozzarella, and pesto. Adjust seasoning to taste with additional salt and pepper. Continue heating on low, stirring frequently, until spinach leaves are wilted and sauce has thickened slightly. Do not boil!
Fold in cooked ravioli and gently toss to coat.
Spoon ravioli into pasta bowls, sprinkle with parsley and red pepper flakes, and serve hot.