I have two favourite ways to preserve tomatoes. Either in a simple tomato sauce or sun-dried. Sometimes I make the effort to put them outside, but mostly I do the lazy, and quicker, oven method. If you have several varieties of tomatoes it is better to separate them as the big ones will take longer.
Traditional, Outside Method
The important part here is to have enough air flow around the tomatoes. Fine mesh is the ideal, but I have used a dish drying rack with cheesecloth on it and when we were in Italy I saw this great idea using a clothes drying stand and shade-cloth
Cut the tomatoes in half length-ways and scoop out the pips and wet parts. Lay the tomatoes face up on the rack and cover with another mesh, or a sheet of cheesecloth. In Italy they don’t cover them, but I don’t like the idea of bugs landing on my tomatoes!
Leave them in the full-sun and bring them in every evening or they will get damp with the morning dew. They take about 10 days to dry out. You can either put them in a jar with olive oil or store them as is.
Cut the tomatoes in half length-ways. scoop out the seeds and wet part. Lay them face up on a baking tray. Sprinkle with a little salt and drizzle with a small amount of olive oil. Some people add herbs at this stage too. I rather put them into the jar at the end as I don’t like crispy herbs.
Put them into your oven at the lowest setting and leave for 6-8 hours. They will be dried and crinkly around the edges.
Oven dried tomatoes tend to retain more moisture so I always put them into olive oil and, if I remember, add a sprig or two of herb.