Active Time

　　30 min

　　Total Time

　　30 min

　　Allow this salad to sit a few minutes after tossing; the mozzarella milk and tomato juices emerge and add flavor to the dressing.

Ingredients

　　2 tablespoons red-wine vinegar

　　1 teaspoon Dijon mustard

　　1 teaspoon salt

　　1/2 teaspoon sugar

　　1/2 teaspoon black pepper

　　1/2 cup extra-virgin olive oil

　　4 lb mixed heirloom tomatoes, quartered if small or cut into 1/4-inch-wide wedges if larger

　　1 lb cherry tomatoes

　　1 lb very small mozzarella balls (1/4 inch; sometimes called perlini) or 1 lb lightly salted mozzarella, cut into 1/4-inch pieces

　　1 1/2 cups loosely packed small basil leaves or torn large leaves

　　Whisk together vinegar, mustard, salt, sugar, and pepper in a large bowl. Add oil in a slow stream, whisking constantly until dressing is emulsified. Add tomatoes, mozzarella, and basil and toss well. Season with salt and pepper.

　　Cooks' notes:

　　•Salad, without vinaigrette, can be assembled 2 hours ahead and kept at room temperature. Salad can be dressed 1 hour ahead and kept at room temperature, covered.

　　•Vinaigrette keeps, covered and chilled, 1 week.