Preheat oven to 400°F (200°C). Line a rimmed sheet pan with parchment paper.
Toss tomatoes directly on the prepared pan with olive oil, balsamic vinegar, garlic powder or smashed garlic, sugar, salt, and pepper. Use your hands to mix until evenly coated.
Spread tomatoes in a single layer, cut side up as much as possible. Roast for 18–22 minutes, tossing once halfway through, until skins are blistered and tomatoes look jammy.
Cool slightly to room temperature. Taste and adjust salt, then toss with fresh basil if using. These are best served at room temp and added to your favorite dishes; see note 1 for ideas.
Notes
Note 1: Try these on buttered toast with parmesan and basil, over burrata with pesto, in grain bowls or pasta, over cottage cheese with a drizzle of balsamic reduction, or with eggs. They're also great on pizza, sandwiches, or stirred into hot pasta.Storage: Store in a sealed container in the fridge for up to 5 days. To freeze, spread cooled tomatoes on a lined tray, freeze until solid, then transfer to a freezer bag for up to 3 months. Enjoy cold, at room temp, or gently warmed.