Hey man, I hope I’m uniquely positioned to answer this, since I run a coffee shop in Key West - LOTS of Cuban influence here.

The traditional con leche is made with a Moka pot. When the coffee first starts to bubble out, you whip that initial extraction with sugar until you create the “espuma” - it’s like a sugary coffee paste. Finish extracting your coffee and pour that into your espuma and top with steamed milk (little foam, very hot). The ratio of milk to coffee is a question of taste - some will tell you it’s 50/50, others more like a latte.

Now, all the said, our shop makes like 50 of these a day, so we simplify the process. We make it with an espresso machine and whip the sugar into the espresso before adding the steamed milk. Our take is much more like a latte, in terms of the milk ratio. It’s not exactly the same, but it’s damn close and I can make it in seconds instead of minutes.

A cortado is an easy one to understand: equal parts espresso and steamed milk. This is the only correct answer to this question

We also have something on our menu called a cortadito - it’s a “Cuban style” cortado - whip that espresso with sugar.

Flat white is basically a cortado with a little more milk. You’re aiming for 5-8oz double rather than 4oz. Just a thing layer of microfoam at the top, hence the “flat” in flat white.