In a 1979 article by Elizabeth David on A True Gentlewoman’s Delight: “How to make a Florentine,” a mid-17th century cookbook, describes a dessert cake made with veal and sheep kidneys, cream, sugar, eggs, berries, rose water and a whole host of spices. Closer to a reliable source for a recipe for florentines I have not come. Why that was called a florentine remains a mystery, but the fact is that it bears no resemblance to the brittle lace cookies with melted chocolate that we call florentines.
The main ingredients of what we call florentines today are not remotely Tuscan: cream, butter and chocolate.

It is much more likely that today’s florentines originated in France, the country with the myriad pastry shops known for selling the world’s most delicious pastries made with cream and butter, from scrumptious croissants to chocolate éclairs to heart-shaped palmier pretzels. Not only are the ingredients typically French, but the fact that the base for florentines is actually a typically French roux points to the true origins of this fine cookie for coffee.
And really, it wouldn’t be surprising either that the French named a dish after Florence. After all, they did so for centuries under the influence of their Florentine queen Catherine de’ Medici, who also happened to be one of history’s most influential gastronomes.

The name “florentine” almost certainly refers to the gold coins from Florence, which were the standard means of payment in Europe for some five hundred years.

An Austrian line of thought is also quite plausible: Florentine coins were copied en masse in the German territories and Italian and French delicacies were also in great demand there, but the preparation method of the cookies is more akin to French preparations.
‘Florentines are attributed to Austrian bakers but their origins are in Italy. They consist of a delicious mixture of sugar, butter, cream, nuts and fruits. They are nice and crispy and traditionally, but not always, have a chocolate base.’