These flavorful tomatoes are great to have in your back pocket on a busy weeknight. They take any pizza or pasta to new heights.
Preheat oven to 250 degrees with racks in upper and lower thirds. Fit 2 parchment-lined rimmed baking sheets with wire racks. Divide tomato slices evenly between racks. Drizzle both sides with oil. Season with salt and pepper; scatter thyme over top.
Bake, rotating sheets halfway through, until tomatoes are dry (but not crisp) and wrinkled, about 3 1/2 hours. Let cool completely.
Transfer tomatoes to a parchment-lined rimmed baking sheet; freeze until firm. Stack in airtight containers and freeze up to 1 year.