Sant'Ambrogio is where Florence buys its dinner, and the antidote to everything wrong with eating in the centre. East of Santa Croce, past the tour groups' last reach, it runs on one cast-iron market shed and the cooks who circle it.
Start in Piazza Ghiberti before ten, while the outdoor stalls are still going up, then go in under the iron roof of the Mercato di Sant'Ambrogio — flowers and vegetables in the colonnade, the butchers and cheesemongers within. This is a working market; you point, the stallholder picks. Just outside, the trippaio does lampredotto in a bun, dunked in broth — the city's true street food, eaten standing. Don't overthink it; order, dip, lean on the counter.
Then Via dei Macci and the Cibrèo corner, Fabio Picchi's restaurant, cheaper trattoria and café all within sight of each other. Cut up to Piazza dei Ciompi, named for the wool-workers who rose up in 1378, and finish at the church of Sant'Ambrogio — a Mino da Fiesole tabernacle, an empty nave, the quietest two minutes on the walk. The bus into town is on the square.