In a large pot over medium heat, add the onion and celery with a small splash of water and cook for 3–4 minutes until they begin to soften.
Stir in the garlic and cook another minute until fragrant.
Add the potatoes, cabbage, peas and the water or broth. Bring to a gentle simmer and cook for about 12–15 minutes, until the potatoes and cabbage are tender.
Blend about one to two cups of the soup and return it to the pot to create a naturally creamy texture without using cream.
Stir in the fresh parsley and season with salt, pepper and a squeeze of lemon if desired.