It’s dry-farmed tomato season, which means I’m making big batches of Susie Bright’s roasted tomato sauce. This recipe is amazingly delicious and ridiculously easy — about 10-20 minutes of prep depending on how much you’re making, plus blending at the end. And it freezes really well, so whenever it’s tomato season, we make giant batches of it and freeze it for the winter.

You know that children’s book, Frederic, about the mouse who sits around in the summer gathering words and colors and sun rays to store up for the winter? That’s what this sauce feels like. When winter comes, and it’s been gray and cold and wet for days on end, we stick some tomato sauce in the microwave and put it on pasta, and it feels like pulling a bit of stored summer out of the freezer. And when the sauce is roasting, it fills the house with this ambrosial tomato perfume. We mostly make this to freeze, but we can never resist eating some of it right away, warm out of the oven.

I got the recipe from Susie Bright, and have adapted it over the years. Here’s my version.

Slow-Roasted Tomato Sauce

Ingredients

4-5 lbs red tomatoes, ideally dry-farmed (see Notes below)
3-5 red bell peppers
1-2 heads garlic
1-4 onions, depending on size (I usually use two)
Olive oil
Salt
Balsamic glaze, or balsamic vinegar plus a little honey or sugar
Fresh basil
Fresh oregano
1 tsp or less sugar, to taste (optional — see Notes on Charring below)

Instructions

Cut tomatoes, peppers, and onions into large chunks (halves or quarters); put in large roasting pan. (You don’t need to skin the tomatoes or peppers — just cut out the stems and seeds.) Peel garlic and add whole cloves. Add olive oil, enough to coat all vegetables, plus salt to taste; mix thoroughly to coat (I smoosh it around with my hands). Arrange so onions are covered by peppers and/or tomatoes (otherwise they dry up).

Roast uncovered at 250F for about 4 hours, until vegetables are soft. (See Notes on Charring below.)

Drain out liquid (tomato liquor); set aside to use separately.

Chop fresh basil and oregano coarsely; add to sauce, along with a good drizzle of balsamic glaze. Blend sauce with stick blender, more or less depending on the texture you like. Add back tomato liquor as needed to get texture you want. Adjust salt, herbs, and balsamic glaze to taste. Add a small amount of sugar if you think it needs it.

Notes and Variations

If you can possibly get them, use dry-farmed tomatoes. The flavor is super-concentrated, and they have a solid texture, perfect for this recipe. Otherwise, get any good-quality red tomatoes that are more meaty than juicy.

Make sure all tomatoes and peppers are red. We did mixed-color heirlooms once, and while the sauce was delicious, it was a weird, murky color.

It’s lovely to roast the garlic ahead of time, and add it at the end with the herbs. You can do this instead of putting raw garlic in at the beginning, or in addition to it.

You can also caramelize some onions and add them at the end with the herbs. (You may want to use fewer onions at the beginning.)

I chop my herbs before adding them to the sauce — if I don’t, I have to blend the sauce smoother than I like. If you prefer a very smooth sauce, you can skip this step.

Tomato liquor is lovely in soups, sauces, chili, etc.

If you want the balsamic glaze roasted in with the other flavors, you can add it at the beginning with the olive oil. I prefer to add it at the end: it’s a strong flavor and I want to control it carefully, especially with the charring technique (see Notes on Charring below). If you want to use tomato liquor in things that argue with balsamic, definitely add the balsamic at the end, after draining the tomato liquor out.

For a little bite, add a couple/few hot peppers before roasting.

I used to blend the sauce right in the roasting pan. Lately I’ve been transferring it to a tall-sided bowl first; it cuts down on splashing.

If you don’t have a ginormous roasting pan (ours is 16″ x 12″ x 4″), you can halve this recipe.

Notes on Charring

I was making this sauce recently, and accidentally set the temperature to 350F instead of 250F. The entire top layer was scorched and blackened, not in a nice way but in an inedible way. I tried to salvage it by removing all the blackened bits, which was about half the total vegetable matter.

And what was left was FREAKING AMAZING. The flavor was deep, smoky, and super-intense. It was the best sauce I’ve ever made.

So I embarked on a series of experiments, trying to re-create that charred flavor without wasting half the vegetables. With the help of friends on Facebook (thanks, everyone!), I came up with three techniques. They all work well, with their own plusses and minuses.

With all three methods, more liquid will be cooked off than usual — you’re not going to get the tomato liquor that results from the usual technique. I also add the balsamic glaze at the end, not the beginning: the flavor is already intense and it doesn’t need much balsamic. I also add a little sugar: the char seems to demand it, or maybe I’m just using less balsamic glaze. Depending on your oven, you may need to move the veggies around in the pan to get even charring. And with Methods 2 and 3, the top layers of the onion chunks may be dried and leathery, even if you cover them carefully — just discard them.

Method 1: Char tomatoes and peppers first, remove charred skins, then do usual slow-roast. Slice tomatoes in half, place cut-side down on baking sheet, and broil until charred, about 5-10 minutes. (You may need to move them around on the pan every couple of minutes to get an even char.) Repeat with chunks of red bell pepper. Remove blackened skins, but don’t be perfectionist about it — it’s good to leave some charred bits. Or you can leave them if you really like the char. Make sauce as usual.

This worked really well: the result was very yummy and highly concentrated. But it was a non-trivial amount of work.

Method 2: Do usual slow-roast at 250F, but for longer — 6 hours instead of 4. Literally just follow the standard recipe and cook for longer.

This came out really yummy, similar to charring the vegetables ahead of time with less work. But it did come out thicker than usual, testing the boundaries between sauce and paste. That’s not a bad thing, but it’s not always what I want.

Method 3: Do usual slow-roast at 250F for 4 hours — then turn up heat to 350F and cook until desired char is reached, about another hour. (I also raise the rack closer to the flame when I turn up the heat.)

This works really well for me. It doesn’t reduce the liquid as much as the other methods, so the result is less dense and more of a traditional sauce. It’s not as powerful of a charred taste as the other methods, but that’s adjustable, I could just cook it at the higher heat a little longer.

If you’ve made this sauce and have varied the recipe in any way, let me know in the comments. And many thanks once again to Susie Bright!