I've roasted a lot of tomatoes this year, because that way we'll have some summer sunshine in the depths of winter. About this time last year I decided that we would never again eat anything out of season, nor would we eat any more air-freighted food. I didn't then realise how boring we would find our winter diet, because I had made no preparations. By spring, everyone was longing for salad leaves, and, above all, for tomatoes (they're just not the same out of a tin, useful though those are).
This year, I am determined that we won't have such a restricted winter palate. One of the things I have been doing is roasting tomatoes for the winter. Some are stored in jars of oil in the fridge, but, this year, while the learning curve is still steep, most are in boxes in the freezer (some are frozen whole, others are already made into sauce).
I've tried several different ways with roasting, and have found that slower really is better. One problem with true slow-roasting is that taking 12 hours to cook a tomato isn't always convenient - you either have to be cutting up toms first thing when you're barely awake, or last thing at night when you'd much rather be brushing your teeth and going to bed. So I've experimented with faster/hotter.
For all these tomatoes, you prepare them the same way: cut them in half, put them cut side up in a roasting pan, sprinkle them with thyme and olive oil. If you like you can add some unpeeled garlic cloves, particularly if you're going to make tomato sauce at the end. If you like you can peel them when they're cooked, but I don't often bother.
Many many people leaving comments on my blog say that they'd like to cook from scratch but don't have time. This is an easy way to begin (and it's not too late to make a start this year, although there's probably only another week or so in southern England). When there's time and energy, a little effort - 10 minutes in two bursts - gives easy fuss-free ingredients for the days to come. You can re-heat them and use them as a vegetable (great on toast for breakfast), or snip them into salads, or onto pasta for an instant sauce.
I've written down the pros and cons of the various ways to roast tomatoes, mainly because I'll have forgotten by next summer, but also to help you with any end-of-season glut. I wonder if it would work with green tomatoes? Please let me know if you have any information on that.
Here's a list of findings:
1. Alanna's slow-roasted tomatoes are the best, the Rolls Royce of tomato roasting. Put them on at 100C max, and they'll take at least 12 hours, depending on their size.
2. Hugh Fearnley-Whittingstall's method given in the Guardian on 18 August 2007, is to put them in a medium oven 180C for 45 minutes to an hour. This is fine if you are in a hurry, but doesn't bring out all the sweetness of the fruit, so makes a slightly uninteresting result (this is the counsel of perfection, they're fine, it's just that you can do better for no more real effort). Great for when you're going on to make ketchup or sauce.
3. Skye Gyngell says that she slow-roasts tomatoes at 100C for 3-4 hours. I haven't tried this, because I can't believe you'd get a good result after so short a time at that low temperature.
4. Nigella Lawson has something she calls moonblush tomatoes. Here, you put them into a very hot oven, 220C, and switch it off straight away. You then leave them for 12 hours. This is best done overnight, because it is really important that you don't disturb them until everything has come right down to room temperature. I did it with small tomatoes, as specified, and had to give them a bit of a blitz in a warm oven at the end. I think you'd need to use cherry tomatoes for a decent result. That said, it's a useful way of using residual heat from the oven if you've been cooking in the evening.
5. When Sarah Raven roasts cherry tomatoes for pasta (with balsamic vinegar and honey added to the usual ingredients specified above), she pricks them all so that she can skin them easily when they're cooked, and she puts them in at 180C for 20 minutes. Hmm. But in her defence, she's not actually cooking these to conserve.
6. Mary Berry's Aga-Dried Tomatoes specify six hours in the simmering oven, which should be 120C. I have done this, and it works. Not so long as Alanna's recipe, so easier to fit into your life. A good compromise.
7. 2-3 hours at 150-160C is even easier to fit into your life, and much better than one hour at 180C.
All of these can be stored completely covered in oil in a sealed jar kept in the fridge. They should last 3-4 months. The tomato-y flavoured oil can be used for cooking. They can also be stored in boxes in the freezer. You can make them into sauce and ketchup before freezing if you like.