Have you noticed how certain dishes suddenly start to appear at a wide variety of restaurants, dishes that you hardly ever saw previously at an upscale restaurant? I figure some hot shot place started something and then it got copied. Here are a few of my current examples. Please add to the list.

Mushrooms - For a while it was shiitake that was in. More recently, shiitake are passe and portobello are in.

Bread pudding - That dessert your mom used to make has now become gourmet, with all sorts of special flavors and varieties.

Mac and Cheese - This is the one that surprised me the most in the past few years when I first saw it. Again, all sorts of additions, especially lobster to justify the price.

I'd also be curious if anyone knows where some of these actually got started.

Peasant dishes - things like beef/veal cheeks, short ribs, polenta. any meat that needs to be cooked for a very long time to become tender.

Pork belly is all the rage in Southern California

Seems that every restaurant is required to serve tiramisu regardless of the ethnicity of the restaurant

Foams

Aren't those "slider" burgers en vogue now at high end places, as well?

Sliders in... foam out.
Am seeing duck sliders, pork belly sliders and, of course, burger sliders. Foam is so over that even the guru in Spain has moved on.

Chocolate volcano cake,the fad of the 90s, is still here.

Yes - mistakenly ordered these recently. Little more than White Castle hamburgers (supposedly with Kobe beef) for $18!!

The bubbly waitress at one restaurant last month was aggressively pushing "sliders". I asked what was a "slider" and had she ever eaten one. She admitted to never eating one and said she would ask chef. Ten minutes later the bubbly one returned and sez we would really like them. Again I asked what is it. She sadly went into an un-bubbly state and described it as probably a small hamburger. She admitted it cost the same as a regular sized hamburger but came without french fries.

MisterNice

I've seen a lot of Nobu inspired miso-glazed (insert fish) and new style sashimi/crudo at a lot of mid-tiered restaurants.

Salumi & charcuterie .

IMO, it's a waste to put lobster in mac and cheese. Lobster has a very delicate flavor and cheese is pungent and strong which overpowers the flavor of the lobster.

I had lunch at Jean-Georges at Columbus Circle last week. It's still on the menu. I ordered it and it's still divine.

Beetroot. Everything is stained purple, even desserts. If I wanted beetroot, I'd have a burger in Australia.

Foams make me angry: they lack flavour, fall quickly, and make it look like frogs had sex on my plate.

Sliders can be lovely, but are often appallingly overpriced. I happily ate a $10 appetiser plate of 2x duck/beef and 2x pork sliders served with a very tangy relish. Would I pay $18 for a single slider? Nope. Don't care if the cow was worshipped by blind nuns and invented calculus. It's not worth it.

Chocolate volcano cake. Rich. Spongy. Chocolatey. Yum! But certainly not always what I want. Best dessert I've had in recent memory was a beautiful boozy pina colada sundae with heaps of coconut and lemon sorbet.

Offal is trendy, but if you can't do it right (and a lot of places can't), then don't bother. It's foul when done wrong.

There's a trend at the moment for spicy cocktails with loads of chilli, tabasco etc. To me, it's always overpowering and destroys the flavour of the cocktail. Something I'd drink on a bet, not because I wanted it.

Edit: Also, savoury ice creams with main courses. They're hard to do right. In fact, I have yet to taste them done right. Just give me steak...I don't want mustard ice cream.