I can only assume that the invention of this dish was on the back of a heavy night of too much drinking.
The Francesinha (or little french lady) is far from little and not very feminine.
I can imagine the drunken conversation.
“Let’s make a sandwich. Some ham. Some cheese. Ok some salami. What else have we got?”
“Some sausage. What about a steak?”
“This all looks a bit stodgy. Lets pour some cheese and beer sauce over the top. And then grill it”
It may not be a culinary masterpiece but it is a classic dish of Porto.
Survival Rations 