Or, a kind of dessert that deeply resembles a loaf of bread only it's a lot sweeter, softer, and contains candied fruit... Which aren't actually fruits at all.
1) A person digs through trash and eats it. Observer says, "Dude, what a fruit cake!"
2) Why a 'fruit cake' is called a fruit cake is a mystery since it isn't really a cake, and it doesn't even have fruits inside.