Roma (plum) tomatoes tend to be meatier than other tomatoes, with less juice and seeds, making them the best candidates for roasting. You can roast tomatoes slowly at a low temperature, or crank up the heat and get them done more quickly, although the flavour isn’t quite the same. Slow roasting brings out their sweetness and rids them almost entirely of their acidity.
Roma tomatoes (as many as you want to roast)
Olive or canola oil
To slow-roast your tomatoes, preheat the oven to 250F; to roast them more quickly, preheat the oven to 400°F. Cut the tomatoes into halves or quarters lengthwise and lay them on a rimmed baking sheet. Drizzle with oil and toss gently with your hands to coat the tomatoes well.
Sprinkle with salt and roast for 4 to 6 hours at 250°F or for 1 hour at 400°F. Cool and store – along with the juices and oil that have collected in the bottom of the pan – in a sealed container in the fridge.