This dish can't get easier. That's the beauty of authentic Greek cooking. They eat from the garden and cauliflower is a winter vegetable grown in Greek gardens. It's always in my garden as well. If you wish, you can add potatoes, cooked garbanzo beans, or fresh peas.
In a large saucepan, add the olive oil and saute the onion and leek until softened.
Add the cauliflower florets, tomato sauce, water, cinnamon to the pot.
Cover pan and simmer until tender, 35-45 minutes.