In the culinary arts, the word Florentine (pronounced "FLOR-en-teen"), or the term à la Florentine, refers to a recipe that is prepared in the style of the Italian region of Florence.
The easiest way to remember what it means is that a Florentine-style recipe features spinach.
Specifically, a dish prepared à la Florentine will feature some main ingredient, such as eggs, poultry or fish, served on a bed of spinach which has been cooked in butter, then topped with Mornay sauce and grated cheese, and finally browned under the broiler.
One common dish with the Florentine moniker is eggs Florentine, a variation on eggs Benedict featuring a poached egg served over a bed of spinach (in place of the ham) on a grilled English muffin. It's served with Mornay sauce instead of hollandaise sauce, although it's not uncommon to find it served with hollandaise in a lot of restaurants.
And while spinach is characteristic of a dish prepared à la Florentine, a pile of steamed spinach is a far cry from the traditional Florentine method of gently simmering the spinach in melted butter. And not cooked and then a little bit of butter stirred in. Simmered in butter.
If that sounds decadent, consider that the technique is said to originate with Florence-born Catherine de Medici, or rather her chefs, who accompanied her to France upon her marriage to the Duke of Orleans and future king.
Spinach is thought to have been brought to Sicily by Arab merchants over 1,200 years ago, and the plant thrived in Italy, Spain and elsewhere across the Mediterranean region.
Thus spinach is not so much a Florence thing as a Catherine de Medici thing.
Even so, I can't help wondering which scenario is more plausible: that the future queen of France, aged 14 at the time, was so devoted to spinach that she endeavored to bring bundles of it with her to her wedding (indeed, in some versions of the legend, such is teen-aged Catherine's preternatural obsession with the leafy vegetable that she brings spinach seeds, with an eye toward cultivating them after the nuptial ceremony);
OR, that upon arriving in Marseille, the site of the wedding, her chefs discovered an abundance of spinach, owing to the similar Mediterranean climate, and went ahead and cooked with it because it was a familiar ingredient.
I hate to debunk these beautiful legends, but honestly I think the latter is much more likely, don't you?
In any case, strictly speaking, in addition to buttered spinach, a Florentine-style dish needs Mornay sauce, grated cheese and an au gratin finish. Which means the version of eggs Florentine described above, is technically just eggs with spinach. But don't mention this fact to your server at brunch this weekend, because I guarantee they will not be amused.
Note that the word florentine also has another definition not related to recipes made with spinach and Mornay sauce. There's a thin, crunchy wafer or cookie that also goes by the name florentine. This florentine cookie is made with honey and nuts and is sometimes coated with chocolate.