In 1889, pizza had not yet become a popular or well-known dish, and was typically eaten by poor people as a way to use up various ingredients that would otherwise go to waste. At that time, Esposito was considered the premier pizza-maker in the city of Naples.
Esposito was therefore requested to prepare a pizza for Queen Margherita of Savoy, who had traveled to Naples with King Umberto I. Esposito and his wife were admitted to the royal kitchens to prepare this dish as he saw fit. Deeming the traditional garlic topping to be unfit for the royal palate, Esposito instead prepared three different pizzas, the last of which used a combination of tomatoes, mozzarella cheese and basil to emulate the red, white, and green of the Italian flag. It is claimed by some sources that this was the first time pizza was made with mozzarella cheese.
Queen Margherita, having never had pizza before, so enjoyed the dish that she had her head of table services send Esposito a letter to commend his pizzas, stating that they "were found to be delicious". Esposito used this recommendation to successfully promote his restaurant, naming the pizza most enjoyed by the Queen, "Pizza Margherita".
It is widely reported that this event caused pizza to become a fad, from which it retained enduring popularity. Because of Esposito's experiments with ingredients and presentation, and his successful preparation of the dish for Queen Margherita, it is suggested by some that Esposito was the father of the modern pizza. Esposito's restaurant still exists, although the name has been changed to Pizzeria di Brandi, and the royal letter favoring Esposito's pizza is on display in the restaurant.