PREP OVEN: Preheat the oven to 275°F. Line a large rimmed baking sheet with parchment paper or a silicone baking mat.
SEASON TOMATOES: In a large bowl, add the halved tomatoes, minced garlic, 2 teaspoons sugar, 1 ½ teaspoons kosher salt, and ½ teaspoon fresh ground black pepper. Pour in ¼ cup extra virgin olive oil and 1 ½ tablespoons balsamic vinegar. Gently toss until the tomatoes are evenly coated and glossy.
ARRANGE: Place the tomatoes cut-side up on the prepared baking sheet in a single layer. Spoon any remaining oil and vinegar mixture from the bowl over the tomatoes.
ROAST: Bake for 2 hours, until the tomatoes look shriveled around the edges, deeply red, and lightly caramelized. They should smell sweet and concentrated, not burnt. Remove from the oven and let cool to room temperature.
PREP MOZZARELLA: Slice the mozzarella into slices just under ½-inch thick, then cut each slice in half.
ASSEMBLE: Arrange the roasted tomatoes and mozzarella alternately on a serving platter. Scatter the sliced basil over the top.
FINISH AND SERVE: If desired, drizzle lightly with extra olive oil and add a pinch of fresh ground black pepper. Serve at room temperature.
Notes
Make-Ahead: The roasted tomatoes can be made up to 2 days ahead and stored covered in the refrigerator. Bring to room temperature before assembling.Storage: Store leftovers covered in the refrigerator for up to 2 days. Basil is best added fresh just before serving.Ingredient Note: Roma tomatoes work best because they are meatier and less watery. Do not core them, it helps them hold their shape while roasting.Serving Tip: This salad is best served at room temperature so the olive oil and mozzarella stay soft and flavorful.