There aren't many famous places to have a nice large American breakfast in Florence. The few that I know are for sure The Diner. The food is authentically made from the french toast to the to die for hamburgers. It is open continually throughout each day. There is no reason to rush to make sure it is open at in the middle of the day. There is a crowd during the weekend for sure. The place is definitely frequented by many students as well as the locals. The prices are ok, but to be honest it's a bit more expensive than in the States. The milkshakes are delicious!
Angels Restaurant has a giant spread for their brunch special on Sundays. From 12:00 to 3:00pm there is a grand brunch. You must reserve since there is limited seating as everyone goes there on Sundays. It is incredible how popular brunch is now in Florence. Brac has a smaller selection but the quality is amazing. They serve french toast and pancakes with jelly and honey, a cup of fresh yogurt, granola and fruit. As an ending to a lovely Sunday, they offer a sweet dessert of the day.
Cuculia fuses Japanese and Mediterranean food together. Their brunch is a bit more unique. You won't find pancakes on this menu. They serve more lunch type food. For example a dish something like this: cream of pumpkin soup, boiled cabbage and zucchini, chicken and coconut rice with raisins and cinnamon.
Although these aren't especially what you think of as brunch, these locales have made it their to make brunch their own creation. So go ahead, stop by one of these ten places and enjoy a different type of brunch with a bit of Italian style added right in.
Via dell'Acqua 2/r
Brunch catering to the student population with all kinds of food from home...
Via del Proconsolo 29/31
Fusion Food in a modern environment in Florence...
VIa Serragli 3R e 1R
Integrating art, poetry, traditions and food...
Via dei Vagellai, 18/r
A vegan experience with the convenience of wifi as well...
Via 27 Aprile 65/67r
Cafe with a delicious brunch served on the weekends...
Via Mazzetta, 5a
A Fusion and Tuscan style restaurant...
Via di San Niccolò 55r
The first American bar in Florence back in 1981...
Piazza di Santa Maria Novella, 7
Brunch with buffet and eggs any style...
Lungarno Corsini, 12r
A dark bistro with DJs throughout the weekend...
Via dell'Isola delle Stinche 9r