Francis Lam has a confession: He doesn’t like to can. The Gilt Taste editor may spend his days touting the glories of caramelized watermelon salad and chatting about food and culture with chef Eddie Huang, but a home canner he is not.

“I can’t tell if I should admit to not doing it because … it’s kind of like, ‘Oh, you’re a food person, you’re supposed to be canning and preserving,’” said Lam, who added that he probably only goes through the old timey process once every three years.

That’s not to say Lam isn’t willing to put in a significant amount of work in order to squirrel away tomatoes in some form for the winter. He just prefers to spend his hours slaving over a hot stove to make tomato paste. But his aversion to canning may stem from more sartorial origins. 

“I think that [canning] is great, absolutely,” Lam said. “But the whole standing over the stove with the sweat and the steam and, like, I don’t own gingham, like it’s not really my speed.”

Wardrobe concerns aside, though, why spend the same amount of effort to make tomato paste? Lam recently wrote that his girlfriend’s reaction to his endeavor was, “Congratulations! You just made tomato paste. It’s cheap and comes in cans.”

Lam said it all comes down to taste. Forget the sad, sour flavor of canned tomato paste. In fact, he doesn’t even consider the end result to be tomato paste at all. Instead, he refers to it as “tomato concentrate.” The difference begins in the technique, which was drawn from Lam’s experience making sofrito in culinary school.

“The chef [in culinary school] said, ‘you know, really take the time to cook this down, and what you want to do is make it almost like a jam,’” he recalled. “The idea of turning it into a jam really stuck in my head, like that level of concentration.”

(Photo: Francis Lam/Molly Wizenberg)

That means cooking the tomatoes with olive oil, which adds to the flavor of the final product. “I started [using oil] to help it along, get a little more heat, and help it start cooking,” Lam explained. “But what that does, too, is it emulsifies back into the tomato, and it gives it this real round richness in the flavor, and it kind of tames the edges if it’s a little sour.”

As they slowly cook, Lam said to expect the concoction to start to look like a slippery, bubbly mess. But eventually the sugar in the tomatoes will caramelize and the color will begin to darken.

“[There is] not just this sort of one-note sweetness but it gets more complex and it gets darker,” he said. “And I think those two things really make this taste so much different than tomato paste you would just buy.”

For those who shy away from three hours slaving over the stove for any reason, Lam does offer an alternative: Dried tomatoes. “The really nice thing about making it yourself is that it takes basically no work, and you can really control how dry you want it,” he said. “I think that makes a huge difference.”

Similar to how he insists his tomato concentrate is a world apart from canned tomato paste, Lam maintains that homemade oven-dried tomatoes are a far cry from the chewy, oily sun-dried tomatoes found in so many supermarkets.

In fact, Lam hates sundried tomatoes so much that he referred to their popularity in the ‘80s as  “Red Dawn: The Sundried Tomato Invasion.” While he allows that there may be some acceptable specimens out there, for the most part, “they’re kind of nasty, like often they’re really chewy and, again, really sour.”

So it’s important to make the distinction that what he makes at home is not that.

The process just involved slicing up tomatoes, arranging them on a sheet tray or silicone baking mat, and then letting them shrivel away in an oven on very low heat — “really low, 200 or 250,” said Lam.

The resulting dried tomatoes make for a snack in and of themselves, or can be a flavorful addition to sandwiches.

“I do actually like to do something, like mix it in with eggplant,” Lam said. “[I] cook eggplant down for a long time until it almost basically melts and throw bits of these dried tomatoes in there to give a real spark of a different flavor, of a little acidity to like this really rich eggplant.”

For those looking for a gingham-free, fun way of spending three hours, find Lam’s directions for making “The Bomb Tomato Concentrate” below. You’ll also find his instructions for the more “set it and forget it” process of making dried tomatoes.

The Bomb Tomato Concentrate
by Francis Lam

Makes about 1 cup

• ½ head garlic (optional)
• 1 medium onion (optional)
• 3 pounds super ripe, juicy tomatoes
• ¼ cup extra virgin olive oil
• 2 pinches salt

Cut, chop, puree: If using, mince garlic and onion in a food processor and reserve. Roughly chop tomatoes, and puree them to liquid in the food processor. (If you don’t have a food processor, no sweat. Just finely chop everything, and save as much of the tomato juice as you can.)

Warm oil: In a wide, heavy pot, warm the oil over medium-low heat. You want the pot to be wide so that the water evaporates more quickly. And you want it to be heavy, to cook evenly without scorching (which will really ruin the paste, and your day). If using, add the garlic and onion and cook, stirring, until very soft, 15 minutes or so. Add a pinch of salt. If you want to go full-caramelize on the onions, hey, it’s your world.

Strain tomatoes (optional): If you’re unhappy with tomato skins and seeds, pass the pureed tomato through a fine-mesh strainer. (I won’t judge if you don’t bother.)

Cook tomatoes:  Pour the tomato into the pot, turn heat up to high, and bring to a boil. Add a couple light pinches of salt. Reduce heat to a simmer, give it a stir, and wait. You’ll cook it for a long time, but it’s hard to say how long since tomatoes differ in water content. Bank on 90 minutes or more.

Wait: Wait.

Wait some more: Wait. And stir, too, more frequently as the tomato loses its juice and thickens. I use a heat-proof rubber spatula, since it clears the pot more thoroughly. Keep cooking and stirring. It’ll get thick and annoyingly splattery for a while, as it gets to a pizza-sauce thickness. You can partially cover the pot when that happens, then uncover it again when enough water’s boiled off so that it no longer splatters.

You’re almost there: When it starts to look pasty, you’ll notice that it’ll get stickier. Keep stirring, clearing the pot, mixing back in the thin, darkening layer at the bottom, and spreading the paste out. At some point, it may look like the oil wants to weep out; this is good. When the paste suddenly sticks together like dough and slides around the pot, you’re done. Congratulations!

Store: Turn paste into a dish or bowl and let cool. Pack into containers, press a layer of plastic wrap directly on to the surface, and store in the fridge for weeks, or in the freezer for months. Stir into anything.


Oven-dried tomatoes
by Francis Lam (Photo by Whitney Chen)

Makes about 1 cup of dried tomato slices

2 pounds fresh ripe tomatoes (any variety)
2 teaspoons olive oil, plus more to store, if desired
2 pinches salt

Preheat and slice: Preheat oven to 200⁰ F, or thereabouts. Cut tomatoes into ¼” slices and lay them on a tray or two without any overlap. (A silicone mat, parchment, or nonstick baking sheet work nicely, but aren’t necessary.) Very lightly salt them and dab a finger in the oil and lightly rub it onto the tomatoes, just enough to moisten them. Ew, that sounded grody.

Let the oven do its thing: Put the tomatoes in the oven for about 2½ hours. Halfway or so into it, rotate the trays. Or forget to do it; it’ll probably be fine. They’re ready when they’re like fruit leather: dried, chewy, no visible juice but still a little pliable. If 2½ hours doesn’t do it, keep checking on them every 15 minutes. If you want to speed it up, you can flip the tomato slices at some point.

Store: When they’re done, take them out and let the tomatoes cool on the tray. Store them in an airtight container. Chop and scatter them on anything your heart desires. It’s probably not necessary to keep them in the fridge, but I do, just in case there’s still some residual moisture left in them. You can cover them in olive oil, if you’d like, which will flavor the oil. They keep for months.