Remove the sausages from their plastic casings. Line a plate with a paper towel. Cut the sausage in half lengthwise, then cut into slices, about 1/4-inch thick. Heat 1 tablespoon of oil in a large pot over medium heat. Add the sausage and cook for several minutes until browned. Transfer the sausage to the plate.

Using the same pot, set the heat to medium and drizzle in remaining olive oil. Add the onion, fennel, garlic, celery, carrots, and salt. Cook, stirring occasionally until vegetables are fragrant and begin to soften about 10 minutes. Add the vegetable broth, beans, nutritional yeast, crushed red pepper, sun-dried tomatoes, and rosemary.

When the broth reaches a simmer, add the cooked sausage and kale. Simmer for about 5 more minutes. Stir in the lemon juice and lemon zest and season to taste with salt and pepper. Serve immediately. Store extra in the refrigerator for up to 5 days or freeze for up to 6 months.