"This started out as a clean-out-the-cupboard-and-fridge soup and ended as the world's easiest (not to mention healthier) gumbo. The split peas (which I never really liked before) magically create the thickness, color, and flavor you traditionally get from roux, sautéed peppers, and celery, gumbo file powder, and rice - without including any of them. This tastes even better the next day, as the peas continue to collapse and thicken the broth."
Heat oil in a 4-quart Dutch oven over medium heat. Add onion and salt; cook, stirring, until softened but not browned, about 5 minutes. Increase heat to medium-high. Add sausage and cook, stirring, until browned, 3 to 5 minutes.
Stir chicken broth, split peas, and bay leaves into the Dutch oven; bring to a boil. Reduce heat to low and simmer, covered, until split peas are tender and beginning to collapse, 25 to 30 minutes. Stir in zucchini and simmer until tender, about 5 minutes. Season with salt and pepper. Discard bay leaves before serving.