Instructions:
- Heat oil or butter in a large, heavy-bottomed Dutch oven or stockpot over medium-high heat. Add the sliced sausage and cook until nicely browned on both sides, about 5-7 minutes. Remove the sausage with a slotted spoon and set aside, leaving about 1 tablespoon of fat in the pot.
- Reduce heat to medium. Add diced onion, carrots, and celery to the pot. Sauté gently until softened, about 8 minutes.
- Add minced garlic and dried thyme. Cook for 1 minute until fragrant. Sprinkle the flour over the vegetables and stir constantly for 1 minute to cook out the raw flour taste.
- Slowly whisk in the broth and water to avoid lumps, scraping up any browned bits stuck to the bottom of the pot. Add the cubed potatoes and the bay leaf. Season lightly with salt and pepper.
- Bring the soup to a boil, then immediately reduce heat to a gentle simmer. Cover partially and cook for 15-20 minutes, or until potatoes are tender when pierced with a fork.
- Return the cooked sausage to the pot. Stir in the chopped kale. Simmer uncovered for another 5-7 minutes, allowing the kale to wilt down completely and the flavours to meld.
- Remove the bay leaf. Stir in the fresh lemon juice. Taste the soup and adjust salt and pepper as needed before serving.