Method:
Step 1: Sauté the Aromatics
Heat olive oil in a large soup pot over medium heat.
Add the onion, garlic, carrots, and celery. Cook for 5-7 minutes, stirring occasionally, until the vegetables are softened and fragrant.
Step 2: Build the Flavor Base
Stir in the rosemary and bay leaf. Cook for 1 minute to release their aromas.
Add the chopped cavolo nero, cooking for 2-3 minutes until slightly wilted.
Step 3: Add the Beans and Broth
Add the cannellini beans, broth, and water to the pot.
If using, add the diced potato for added creaminess.
Season with salt and pepper, stirring to combine.
Step 4: Simmer the Soup
Bring the soup to a gentle boil, then reduce the heat to low.
Cover and simmer for 30 minutes, stirring occasionally.
Step 5: Adjust the Texture
For a chunky soup: Serve as is.
For a creamy variation: Remove about 1 cup of soup, blend until smooth, and stir it back into the pot.
Step 6: Final Touches
Taste the soup and adjust seasoning with salt and pepper if needed.
Let the soup stand for 5 minutes to meld flavors.
Variations:
Vegetarian/Vegan: Use vegetable broth and skip the Parmesan garnish.
Gluten-Free: Serve without bread or use gluten-free bread.
Extra Protein: Add cooked sausage or diced pancetta during the sautéing stage.
Creamier Texture: Blend more of the soup or add a splash of heavy cream (or coconut cream for dairy-free).