Do your prep work first. Slice or dice onions and celery, and grate your garlic, or dice it whichever you prefer. Slice your zucchini or other type of squashes, all colors, all varieties work here. Cut up your fresh green beans in half or thirds, whichever you prefer...this will be your recipe.
In olive oil, sautee onions and celery. Add garlic when you add the vegetables. Let them all sautee together until slightly browned. You will need a very large sautee pan, or one of those chicken fryers with tall sides is perfect.
Add the herbs to the mix and stir a little for the aromas to emerge, and then add the tomato sauce, or diced tomatoes and the can of water, enough to cover the vegetables. You can be creative with the veggies as in regular rattatouie. (Personally, I like more mint in mine, so it is your call on the proportion of mint/oregano/parsley.
Cover and bring to a boil, reduce to slow simmer, covering with a lid. Let cook for about 45 minutes to the degree you want your veggies cooked. Mom likes her veggies well cooked, me a little more substance to the veggie please.
Variation: Since this is somewhat like a veggie stew, you could stretch your dollar and add cooked pasta to it, or put the rattatouie over pasta as a vegetarian pasta.