Heat ¼ cup of water in a large pot over medium heat. Add the onion, celery, and potatoes. Cover and cook, stirring occasionally, for 5 minutes, or until softened.
Stir on the nutritional yeast, paprika, thyme, black pepper and vegetable broth. Bring to a boil, then lower the heat to low, stir in the corn, and simmer for 20 minutes, or until the vegetables are tender.
Scoop 2 cups of the solids into a high-powered blender, add the miso paste, and blend until smooth. Stir the pureed mixture back into the soup. Add the lemon juice, then taste, and adjust the seasonings, if needed.
If you prefer a thicker chowder, puree another cup of soup solids and add it back to the pot. Heat the soup until hot and serve sprinkled with parsley.