Bitter frisée tossed with hot bacon, croutons and a sharp mustard vinaigrette, topped with a soft poached egg.
What makes it salade lyonnaise
Frisée — curly, pale and bitter.
Lardons fried until crisp, and croutons in their fat.
A soft egg, broken over at the table to join the dressing.
Where it comes from
It's a bouchon salad, rich enough to be a meal: the heat of the bacon and its fat wilts the leaves a little, and the vinegar in the pan picks up what's left.
Some bouchons add chicken livers, herring or anchovies; the egg is poached, or sometimes boiled soft. The one fixed thing is a sturdy, bitter leaf that can stand up to it all.