Pesto, homemade or store bought gives this soup lots of flavor and the split peas provide lots of fiber. A high fiber diet is recommended during diverticulosis.
In a large soup pot, combine split peas, broth and water and bring to a boil. Reduce heat, cover, and simmer for 20 minutes.
Stir in pesto, zucchini, and green onions; simmer for 15 to 20 more minutes. Garnish with Parmesan cheese, if desired.