Any of these criteria make them a fancy or fancier burger to me:
The $32 price tag
The posh space (high rent)
A brioche bun or a potato bun.
House-made ketchup
Caramelized onions.
A burger that is listed on the same menu as Steak Frites and Coq au Vin.
Hand chopped / minced meat (they can serve it pink if it’s house chopped or minced)
Fancy cheese
Fancy bacon
…
I’ll add some screenshots of examples. These are main course burgers made of good meat. They are not competing with a $7 Single Cheeseburger at Harvey’s, Wendy’s, A & W or McDs.
That said, I still see Fancy Burgers as a Kiddy Menu Item for Adults when they show up on a menu that’s serving well made French food. The demand is there, and it helps the restaurant stay afloat.
I got the $32 price tag from Union Restaurant on Ossington in Toronto. Some burgers come with fries, some don’t.
The going rate for a burger and fries at a chain or independent pub with table service is somewhere between $18 and $25 before tax , so to find a good fancy burger and fries for $25-$30 at a Bistro could be very good value for Toronto. It shows how tight the margin is right now for midrange restaurants.
From Le Select, burger au poivre, $27
Biff’s Bistro, $29
Café Boulud, $49
Café Boulud burger, $49
AloBar, $40
the AloBar Burger, $40
At Union, the Canadian Bistro I visit the most in Toronto, $32
Milou, a mid-range bistro. $24 last year (menu not currently online)
Here in LdnOnt, a fancy burger I have enjoyed, from Craft Farmacy, $26