Bring a pot of water to boil. Once water boils, add the ditalini, and cook them until tender., and drain them from the water. This step can be done while preparing the rest of the soup.
Heat a large pot over medium heat. Add the olive oil. When olive oil is heated and shimmering, add the onions.
Sauté the onions until tender, about 3 minutes. Add the lentils, rosemary and bay leaf to the pot. Season with salt and pepper.
Give the ingredients a good stir, and add the cauliflower. Add the vegetable stock.
Partially cover the pot with a lid and let it simmer over medium heat. Simmer for approximately 20-25 minutes, or until the lentils are tender, but not soft. They will cook for approximately another 5 minutes after this step. Season with more salt and pepper if needed.
Add chard to the pot and stir. Cook the chard for 3-5 minutes, or until tender.
Add the ditalini and give the soup a good stir.
Discard the bay leaf. Spoon the soup into bowls, garnish with parsley or parmesan cheese and enjoy!