Slice each medium tomato into 1/4- to 1/2-inch rounds or into wedges (6–8 wedges per tomato) depending on preferred presentation. Place cut tomatoes in a large mixing bowl.

Slice onion and mince garlic

Thinly slice the red onion into half-moons (about 1/8-inch thick) and add to the bowl with the tomatoes. Finely mince the garlic clove and either add directly to the bowl or rub it into the serving bowl for a subtler garlic aroma.

Tear basil

Stack the basil leaves, roll them into a loose cigar shape, and chiffonade (thinly slice) or simply tear them by hand into bite-sized pieces. Scatter the basil over the tomatoes.

Add lemon

Squeeze the juice of half a lemon over the tomatoes (about 1–1.5 tbs) to add brightness and help hold color.

Make dressing & season

In a small bowl or jar, combine the extra-virgin olive oil (3 tbs), red wine vinegar (1 tbs), Dijon mustard (1/2 tsp), sea salt (1 tsp), black pepper (1/2 tsp) and sugar if using (1/2 tsp). Whisk or shake vigorously until emulsified and slightly thickened.

Taste the dressing and adjust: add more salt for seasoning, a splash more vinegar if you want more acidity, or up to 1 tbs more olive oil for a smoother mouthfeel.

Pour the dressing over the tomatoes, onions, garlic and basil. Gently toss with a large spoon or by hand to coat evenly, taking care not to mash the tomato pieces.

Let the salad rest at room temperature for 10–20 minutes to allow flavors to meld. If preparing ahead, refrigerate for up to 1 hour but bring back to room temperature 10–15 minutes before serving for best flavor.

Assemble & serve

Taste and adjust final seasoning with additional salt, pepper or a squeeze of lemon as needed.

If using, scatter crumbled feta or place spoonfuls of burrata over the tomatoes. Serve with toasted bread or crostini to soak up juices, or serve as a side salad.

Garnish with a few whole basil leaves for presentation and serve immediately.