The weirdest burger toppings in Toronto are a beautiful exploration of what a hamburger can be. In this burger-mad city, we've built them four patties tall, deep-fried them, stuffed patties with rich toppings, made you order them by pulling faces at the counter. But so many of the city's most outlandish burger creations, when you look at their base ingredients, are made from pretty pedestrian stuff (beef, cheese, bacon, bread, bacon, condiments, bacon, and bacon).

Here are my picks for the weirdest burger toppings in Toronto.

Peanut butter
It says something about our city's voracious appetite for stunt snacks that we're no longer shocked by the concept of peanut butter on a burger. In fact, Dangerous Dan's, which predates the current gourmet-burger craze, has been selling Elvis burgers (that's bacon, peanut butter and fried banana; $6.40) at Queen and Broadview for years.

Sandwich buns
As with PB, we Torontonians have also ceased to be fazed by burgers that use sandwiches for buns. That's largely thanks to Burger's Priest and their much-ballyhooed secret menu. Their Vatican City burger shoves a double cheeseburger between two grilled cheeses - there's also a Vatican on Ice, which is an ice cream sandwich on the cheesy buns (you know, for dessert). The Thompson Diner eventually picked up on the idea themselves with a $16 grilled-cheese burger; Holy Chuck, never to be outdone, build their Hawg double bacon cheeseburger ($14.99) on two BLT-bun sandwiches.

Nutella
Peanut butter's classy European cousin is currently enjoying a burger moment - the Fidel Gastro food truck and their Lisa Marie restaurant made major waves when it rolled out a Nutella burger for the first time. Holy Chuck has a spin on it too - curiously for the over-the-top spot, the "Venus My Nutty Cow" ($6.99; still haven't figured out that reference) burger contains nothing but warm Nutella, a patty and a gluten-free bun.

Macaroni and cheese
You could just put cheese on a burger, but where's the fun in that? (Aside from the fun that comes from eating cheese, obviously.) The Works goes for the Can-con with Kraft Dinner (add a scoop for $1.74), and at Gangster Burger, the Pretty Boy Floyd ($8.50) comes layered with mac and cheese, cheddar, chipotle mayo and spicy ketchup (sadly, no cannoli).

Foie gras
Ethically, it's not everyone's cup of tea. But foie gras - duck or goose liver - is still seen as a luxury food item, and if you want to experience it on a burger, there are multiple spots in town that will help you out. At Toma Burger Addiction, the Double Jackpot burger ($19.95) comes with foie gras, bacon, truffle mayo and olive oil, Swiss, and a balsamic glaze (among other things) - you can also add it to a burger for $8.99. Holy Chuck, meanwhile, will let you add it to any of their outlandishly piled-high creations for $9.99, as well as putting it front and centre in their priciest burger: the Holy Duck, which comes with double-smoked bacon, truffle shavings and oil and maple syrup, and rings in at $29.99.

Deep-fried lasagna
While the Ace appears to have discontinued their Guy Fieri-approved mac and cheese burger (so money), in its place is a Black Angus burger topped with a hunk of deep-fried lasagna, San Marzano tomato sauce, mozzarella, and hot peppers ($18). Burger joints with pesto and prosciutto burgers: This shall now be the benchmark by which all Italian burgers are measured.

Maple syrup
In addition to smothering their big-ticket Holy Duck burger in Canada's favourite condiment, Holy Chuck also folds the sweet stuff into a breakfast burger, the Croissant du Paysan ($12.99), which features a fried egg, crispy pancetta, and fries (which I can only guess is a stand-in for home fries), all on a croissant.

Donuts (as buns)
Go back to a simpler time. Before the cronut burger struck fear into the hearts of Toronto eaters everywhere. Before we even knew what the hell a cronut was. The Thompson Diner's spin on a breakfast burger ($12) sees the whole shebang (strip bacon, fried egg and all) served on a powdered donut, which, as we all know, is the breakfast of champions.

Fresh truffles
Not truffle oil, not truffle mayo. We're talking honest-to-goodness shaved flakes of ultra-pungent heaven. Toma opts for black truffles (add them to any burger for $9.99), as well as liberally sprinkling truffle oil and mayo throughout the menu. Holy Chuck, meanwhile, offers white truffle shavings imported from Italy (also $9.99 to add to the burger of your choice). Can you imagine what those two would do if they teamed up? I'm picturing half the contents of Pusateri's on a single burger.

Ghost peppers
Can you handle the hottest of the hot peppers? If you're positive you won't start begging for mercy three bits in, sign up for the Holy Ghost challenge at (you guessed it) Holy Chuck, where you'll be tasked with eating three patties and 7 million Scoville units' worth of peppers and pepper extracts in under 10 minutes. (No drinks allowed until you're done.)

Did I miss any? Leave your favourite wacky burger toppings on Toronto restaurant menus in the comments.

Photo of the Vatican City via the Burger's Priest.