The Larder

Tomato Time Capsule

It’s easier than you to think to take the taste of summer produce into fall


Every year, I single-handedly preserve 100 pounds of tomatoes at the height of the season. I buy them from a local farmer and spend a week packing them in jars, moving them through my dehydrator, and cooking them in various ways to concentrate their sweetness and essential summer flavor.

When I first started this yearly preserving madness, my favorite way to condense the tomatoes was a slow-cooked Italian-style conserva. The finished product looked like grocery store tomato paste but tasted like pure sunny pleasure. That recipe’s one drawback was its need to be touched and tended regularly. I’d devote a weekend to a single batch, simmering, straining and finally cooking ten or fifteen pounds down to just two or three pints of brick-colored, tomato concentrate.

A few years ago, while I was working on my first cookbook, I found that I didn’t have the time or mental energy to make a product that needed to be stirred and smoothed every hour and went searching for a less intensive treatment. The winning technique was a long, slow roasted tomato.

You line a pair of rimmed baking sheets with parchment and cover them tightly with tomato halves. I use Roma, plum, or San Marzano-style tomatoes because they are meaty and hold their shape well. Drizzle each pan with ¼ cup of olive oil and sprinkle fresh herbs (I like to use rosemary, oregano, or thyme) and some crunchy salt over the top.

Tomatoes in oven

Using your hands, rub everything around to ensure that each tomato half has made contact with the oil, herbs, and salt. Tuck five or six garlic cloves (still clad in their papery skins) amidst the tomatoes on each sheet. Roast the tomatoes at 200°F for eight to ten hours. If you remember, you can switch the position of the baking sheets once or twice, but these tomatoes need very little tending.

I realize that might sound excessively long, but truly, half a day of low temperature cooking makes for an incredibly succulent, concentrated tomato bite. When they’re fresh from the oven, I balance them on top of toasts spread with goat cheese and the creamy roasted garlic. Once I’ve eaten all I can hold, I preserve them by packing them into zip top bags and stashing them in my freezer. They are worth every inch of space they occupy.

Finished slow-roasted tomatoes

Once they’re in the freezer, they become one of my favorite ingredients. I rub them into homemade pizza crust in place of sauce. I blend them into a tangy dip with cream cheese and basil. And whenever I have guests for brunch, I bake a crustless quiche with sautéed spinach, gruyere and some of these tomatoes, chopped into bite-sized bits.

Slow-Roasted Tomatoes


  • 8 pounds plum, Roma or San Marzano tomatoes
  • 10 to 12 garlic cloves
  • ½ cup extra-virgin olive oil
  • 1 tablespoon fresh rosemary, thyme or oregano
  • 2 teaspoons kosher or sea salt


Preheat oven to 200°F. Line two large, rimmed baking sheets with parchment paper.
Wash tomatoes and cut them in half length-wise. Arrange them snugly, cut-side up on the baking sheets. Divide the garlic cloves between the two sheets and tuck them between the tomatoes. Drizzle ¼ cup of olive oil over tomatoes, sprinkle herbs and salt and rub it all in.

Place baking sheets in oven and roast for 8-10 hours, until the tomatoes have reduced in mass and look burnished but not burnt. Eat immediately or let cool and freeze according to the instructions above.

Marisa McClellan is a food blogger, freelance writer and canning teacher based in Center City Philadelphia. She runs a website called Food in Jars, where she writes about canning, preserving and delicious things made from scratch. She regularly writes for the Food Network, USA Today, Grid Philly and Mrs. Wages. Her first cookbook, Food in Jars: Preserving in Small Batches Year-Round, is now available.


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