Beefsteak Tomato, Red Onion, and Mozzarella Platter with Basil Drizzle

An August favorite... when basil and tomatoes are plentiful in the Northeast!  This dish is typically served with balsamic vinegar reduction drizzled on top. I prefer to serve it with this tangy dressing my friend, Chris gave me!
Serves 6–8

Dressing
½ cup good-quality mayonnaise
3 tablespoons white vinegar
2 tablespoons whole milk
1 teaspoon sugar
½ teaspoon salt
15 fresh basil leaves
2 tablespoons extra-virgin olive oil
Salad
2 large beefsteak tomatoes, thinly sliced
1 small red onion, thinly sliced
1–2 (16 oz.) logs fresh mozzarella, thinly sliced

Dressing
Place all the dressing ingredients, except the oil, in a food processor and blend. While blending, slowly pour in the oil. Once all the ingredients are incorporated, stop blending, pour into a separate container with a spout, and reserve.
Salad
Assemble the platter by alternately arranging tomatoes, red onions, and mozzarella. Immediately before serving, drizzle the sauce over the platter.
This recipe can be found in Country Comfort: Cooking Across America and Summer Favories.