Try to get evenly sized tomatoes that are ripe and still firm.but not over ripe.To properly roast tomatoes it is necessary to peel and seed them - and remove the interior liquid flesh so that you're left with the thick pulpy part. The tomatoes should be cut in half, then the pieces laid, cut side down side down in a rimmed baking sheet or large pan as shown below. Sprinkle the pieces lightly with coarse salt, drizzle with olive oil (they should be well-coated) and coat with thyme and chunks of garlic. Roast tomatoes at 250F degrees until they've shrunk to about 1/3 their original thickness (about 3-4 hours depending on the size of the original tomato. Turn the pan around while baking (for even cooking) and remove pieces that get done faster than the others. They'll be wrinkled, flat and thin - but still moist inside (not dried). Their color will be brick-red. Store roasted tomatoes in the refrigerator for up to 2 weeks and in the freezer for several months. You'll be suprised just how long they can last in the freezer if properly prepared and stored.