We used a combination of red, yellow, orange, and green tomatoes.
Preheat oven to 200 degrees. Place tomatoes, cut sides up, on a baking sheet lined with parchment paper. Place a garlic slice on each tomato. Scatter thyme sprigs and leaves over tomatoes. Drizzle with oil. Season with salt and pepper.
Bake until tomatoes are shriveled but still soft, about 5 hours. Let cool completely on sheet on a wire rack. Transfer tomatoes to a jar; add oil to cover. Tomatoes can be refrigerated up to 3 days.
To keep oven-dried tomatoes on hand year-round, see our canning instructions at marthastewart.com/canningtips.