Step 1

Heat the oil in a medium pot over medium heat. Add the sausage and cook, breaking the meat up with a wooden spoon, until browned, about 4 minutes. Add the onions and celery and continue to cook, stirring, until the vegetables are softened, about 5 minutes. Add the beans, tomatoes, broth and 4 cups water and increase the heat to medium-high to bring to a simmer. Continue to simmer, adjusting the heat if necessary, until the vegetables are tender, about 10 minutes.

Step 2

Add the tortellini and continue to cook until they are tender, about 10 minutes. Season to taste with salt and pepper. Serve in bowls topped with a spoonful of pesto and a sprinkle of grated Parmesan.