Put all this in a casserole dish and stir in a few generous dollops of tomato puree. Then add the desired amount of harissa paste, Chopped dates, chopped tomatoes and then a good glug of sweet cider. This can be seasoned with salt, pepper and some vegetable bouillon powder.
There should be enough sauce in the dish to coat all the vegetables. Shove the whole thing in the oven for at least an hour, maybe two. It's one of those dishes which you cant really over cook. It should be a sticky, spicy melange of vegetable.
Serve with rice or couscous and a little salad. Pita bread works too.