Prep: Set the frozen spinach out to thaw if you have not done so already. Add the cashews to a medium bowl. Bring 1 1/2 cups of water to a boil and pour over the cashews; set aside to soak for at least 10 minutes. Alternatively, you can place the cashews and the same amount of room temperature water into a bowl and microwave for 2 minutes, then set aside.
Aromatics: In the meantime warm the olive oil in a pot over medium heat. Add the shallot and sauté until translucent, 3 to 4 minutes. Add the garlic, nutritional yeast, red pepper flakes, and black pepper to taste; sauté until fragrant and the bottom of the pot begins to brown, 1 to 2 minutes.
Simmer: Add the artichokes, beans, broth, and 2 cups of the water to the pot; mix well, then cover. Bring to a boil over high heat, then uncover and reduce the heat to medium. Simmer the soup for 10 minutes, stirring occasionally.
Cashew Cream: In the meantime, drain the cashews and add then to a high-speed or bullet blender with the remaining cup of water. Blend on high for 30 to 60 seconds, until a smooth “cream” forms. Set aside.
Make it Creamy: Once the soup has simmered for 10 minutes, add the cashew cream, spinach, and parmesan to the pot. Stir well and simmer for an additional 5 minutes, until the cheese has melted and the soup has thickened slightly. If the soup gets to thick for your liking you can thin it out with additional water.
Final Touches: Turn the heat off and stir in the lemon juice. Sample the broth; add additional lemon juice, salt, and/or pepper to taste, as needed.
Serve: Divide the soup between serving bowls and top with a sprinkle of fresh parsley and extra parmesan. Serve warm. Store any leftovers in the refrigerator in an airtight container for up to 5 days.