Beet & Watermelon-Radish Salad

My mother’s close friend, an Italian woman, once discovered beets and mozzarella being served at one of Mario Batali’s restaurants and adamantly insisted that it was a strange and unallowable combination, too much of a deviation from the classic cooking she grew up with on the Amalfi coast. To me, there is a natural affinity between the earthy beets and creamy mozzarella both in texture and flavor, the fresh milky cheese melting into the dense root vegetable with each bite, offset by the pl