Egg cream - contains neither eggs nor cream
Lake trout - it’s not trout and it didn’t come from a lake (it’s a Baltimore thing)
Others?
Toad in the hole (actually delicious - it’s sausages baked in a giant Yorkshire Pudding)
Sweetbreads - some unmentionable part of a sheep
Sweetmeats - contain no meat
Mince pies - not savoury. Contain no meat
“What’s the deal with Grape-Nuts? There are no grapes and there are no nuts!!!”
Head cheese - contains no cheese.
I’d not heard of this (at least, not the non-trout, non-lake thing), but then, I’m from the Midwest. In Wisconsin, lake trout, as a dish, would definitely have actual lake trout in it. 
They should call it Roundtine!
And why are there two different foods called “truffles”?
Rocky Mountain Oysters
Welsh rabbit or rarebit. Where’s the rabbit? It’s just cheese and bread…
Scotch Woodcock is buttered toast with eggs and anchovies. No woodcock, not even woodcock eggs
I’ve had ones that contain a bit of meat, but more lard than meat.
Shepherd’s Pie does not contain shepherds nor are shepherds the only folk who consume it.
Same goes for Irish Stew, as far as I’m aware. 
when I was a kid I always thought “lady fingers” were a pretty creepy name for these thin little cookie / cake things my family would set out at holidays.
There’s no dog meat in hot dogs. At least not that I’m aware of – who knows what’s in those things!
I can think of two things wrong with the name for pineapple.
One of my very favorite stories from my career occurred when I was in undergraduate business school, at the University of Wisconsin-Madison. We had a guest lecturer in our Market Research class, who was the director of market research at Oscar Mayer (which was also located in Madison).
At the end of his talk, he opened the floor up for questions. A friend of mine asked, “So, what’s really in the hot dogs?” His answer was (and I promise this is, word for word, what he said): “Oh, good stuff, stuff you’d eat…meat.” 
Ragout contains no bits of cloth, nor does ragu.
beat me to it.
- hamburgers are typically made of beef, not pork/ham
- Butterfingers
True, and confusing to kids, though the name doesn’t come from “ham,” but from the city of Hamburg in Germany.
Okay, Mr. Smartypants, then where are bison burgers from? 