Heirloom tomatoes may take a bit more effort than hybrids on the part of gardeners. However, those gardeners can reap some tasty rewards after all that hard work is done. Roasting heirlooms is one of many ways to take advantage of their unique flavors and make the most of them at the dining room table. Best of all, since roasting takes place in the oven, it does not create a mess on the stove.
Heirloom tomatoes are open-pollinated breeds that have had their seeds passed down through generations because of their desirable traits. Flavor, color and hardiness are three such desirable traits.
Roasting is a method of cooking with dry heat in an oven. This method of cooking helps seal in and concentrate a roasted item's natural flavors.
Roasting heirloom tomatoes need involve only three things besides the tomatoes: a sheet pan, a 375 degree F oven and a little bit of olive oil. Tomatoes should have stems and tops removed, and then should be lightly rolled in olive oil. The oil should lightly coat the skin of the tomato, nothing more. Heirloom tomatoes should then be roasted on a sheet pan in a 375 degree oven for about 10 to 15 minutes, depending on size. When the skin turns slightly wrinkly and begins to brown, they are done.
Salt can be added, if desired, but roasted heirloom tomatoes should be tasted before seasoning to determine whether they need it. When they are fresh from the garden, heirloom tomatoes have so much flavor on their own that they may not need much enhancement.
Roasting compounds the natural sweetness of heirloom tomatoes. While they will not be sweet enough that eaters will want to spread them on their toast for breakfast, the level of sweetness will be noticeable. Heirloom tomatoes should be roasted until lightly brown so that they have the chance to caramelize and thus fully realize their roasted flavor potential.
Time needed to roast heirloom tomatoes will vary greatly by size. Concerned gardeners should turn their oven lights on so that they can watch their tomatoes' progress through the oven door, without the need to keep opening it. Opening the oven door causes the heat to drop considerably every time it is done and should be avoided unless absolutely necessary.
Once the skins turn wrinkly, begin splitting and are lightly browned, the tomatoes are ready. These effects will occur no matter what color the heirloom tomatoes were before they went into the oven. Natural sugars in any color tomato will still turn brown as they caramelize.
Roasting should be attempted only after the oven has been fully preheated to 375 degrees F. Any lower temperature and the tomatoes may end up stewing in their own juices instead of roasting. Stewing is delicious as well, but the flavor will not be the same.