Summer Tomato Salad

Ingredients

 * 6 ounces thinly-sliced red onion (1 large)
 * ½ cup distilled white vinegar
 * ½ cup olive oil
 * season salt & fresh ground pepper to taste
 * 6 medium vine-ripened beefsteak tomatoes thickly sliced
 * 6 ounces grated mozzarella cheese

Directions
Place the onions in a small mixing bowl. In a small saucepan, bring the vinegar just to a boil. As soon as it reaches a boil, pour it over the onions. Let it sit until it cools.

When cool, drain the vinegar from the onions into a food processor or blender. With the machine running, add the olive oil in a slow, steady stream, until all of the oil has been added and the mixture is pale and creamy. Add season salt and pepper.

Place the tomato slices on each serving plate. Arrange the onions on top of the tomatoes and sprinkle the cheese over the onions. Drizzle 2 tablespoons of the vinaigrette on each just before serving.