A tiramisu is a sweet lasagna. You have alternating layers of carb and sauce and cheese mixture of some kind.

A shepherd's pie is it's own unique thing as there are no alternating layers and the cheese layers are not mandatory.

The French parfait (different from what you're probably thinking) is a flipped shepherd's pie.

The American parfait is lasagna, as it's usually alternating layers of carb, fruits (with their sauce, often very jammy), and not cheese but a dairy mixture still.