Step 1

Preheat the oven to 400 degrees F.

Step 2

Toss the tomatoes with just enough olive oil to lightly coat, then spread out in an even layer onto a rimmed sheet pan or large baking dish. Roast for 25-30 minutes, until the tomatoes have burst and are just beginning to shrivel. Remove from the oven, tent loosely with aluminum foil, and set aside.

Step 3

Meanwhile, add the 1/4 cup of olive oil to a heavy-bottomed sauce pot. Heat over medium-heat until the oil begins to shimmer. Add the onions and cook, stirring occasionally, until they begin to sweat and soften, about 4-5 minutes. Add the garlic, stir to combine, and continue cooking for another few minutes until the garlic is golden.

Step 4

Add the roasted tomatoes (including all of the cooking liquid in the pan), and the herbs, and stir to combine. Season with salt and pepper, to taste.

Step 5

Turn the heat down to low, partially cover the pot with the lid (leaving about a 1-inch gap), and let simmer for at least 25 minutes – and up to an hour – stirring infrequently as the sauce cooks.

Step 6

Remove the pot from the heat, and let cool for 10-15 minutes. (Carefully!) Transfer the sauce to a blender (or use an immersion blender), and blend until the sauce reaches your desired consistency.

Step 7

Pour the sauce into pint-size canning jars or other air-tight containers.

Step 8

Will keep for up to a week in the refrigerator, or 3 months in the freezer.