Bring a medium pot of water to a boil. Score a shallow 'X' at the bottom of each tomato. Have an ice bath ready. Drop tomatoes into boiling water for 20–30 seconds until skins start to split, then transfer to ice bath. Once cool, peel the skins, core, and dice tomatoes into roughly 1/2-inch pieces. Reserve juices.

Combine aromatics

In a medium bowl, whisk together olive oil, minced garlic, and chopped shallot. Add red wine or balsamic vinegar and sugar if using. Let sit 2 minutes to meld flavors.

Mix tomatoes and season

Add diced tomatoes and their juices to the bowl with the aromatics. Toss gently to coat. Add torn basil leaves, salt, and freshly ground black pepper. Taste and adjust seasoning; add more salt, pepper, or a pinch more sugar if tomatoes are very acidic.

Rest

Let the mixture rest at room temperature for at least 10–15 minutes (up to 1 hour) so flavors marry. If preparing ahead, cover and refrigerate up to 4 hours; bring back to room temperature before serving.

To Serve

If using bread, toast or grill slices until golden. Spoon tomato mixture generously over each slice. Top with slices or pieces of mozzarella or a spoonful of burrata if using. Garnish with extra basil leaves and a light drizzle of olive oil. Serve immediately.