How to Make It
Heat oven to 300°F. Place the tomatoes (cut-side up), oregano, and garlic in a 3-quart baking dish. Drizzle with the oil, 1 teaspoon salt, and ½ teaspoon pepper.
Roast until the tomatoes are slightly reduced in size and the skins are puckered, 1 hour, 45 minutes to 2 hours.
Refrigerate in an airtight container for up to 5 days.