Florence is a city of beauty; even the least corner hides treasures for the eye.  The Mercato Centrale, a downtown food market, is a two-story wonderland of gleaming food stalls.  Tucked into one corner of the orderly arrangement is Nerbone, a lunch counter serving the market’s buyers and sellers since 1874.  Nerbone offers just a few antipasti, primi, secondi, and sandwiches each day.  On a cool, wet November day, I sampled the ribollita–the iconic tuscan bread and vegetable soup–and found their version so thick and delicious, it could have doubled as a sandwich spread.  To chase the ribollita, I opted for a panino bollito, a two-fisted sandwich of seasoned, boiled beef.  This self-service lunch, eaten at a marble-topped table with a view of the butchers and flower vendors at adjoining stalls, cost a whole 7 euros.  Perfection doesn’t have to come at a high price, or with exotic ingredients; Nerbone achieves it through faultless repetition.