It’s rare that someone craving a hotdog would need to have their credit card on them. But to try a new Australian take on the age-old favourite, you’re probably going to have to.

At $100, the Maille Mustard Mobile’s “Haute Dog” is one of the world’s most expensive.

At that price, you might be forgiven for thinking that the grain-fed Australian sausage came adorned with Serbian donkey-milk cheese, Vidalia onion and heirloom tomato relish on a roll made from gold-leaf bread.

In fact, it comes adorned with nothing – nothing, that is, but Chablis-infused black Perigord truffle mustard.

The mustard – which Maille national brand manager Mark Gluck said is the most expensive in the world – is made using French truffles that can only be picked five months of the year, between October and March. Where most mustard is made from ground mustard seeds, Maille cuts them, retaining more of their aroma and flavour. Instead of vinegar, they use the Burgundian white. To reach Australia, the condiment flies first class.

The Maille Mustard Boutique at Mount Eliza sells a single jar of truffle mustard – which retails for the same eye-popping price as the hotdog – each fortnight. It remains the only Maille outlet in the world to have sold a 500g tub of the stuff – at a whopping dollar per gram.

While Maille is touting the Haute Dog as the world’s most expensive sausage-and-bun combo, the Guinness Book of World Records reserves that dubious honour to Seattle-based Tokyo Dog’s “Juuni Ban,” which costs US$169 (nearly A$235).

The Juuni Ban contains smoked cheese bratwurst, butter Teriyaki grilled onions, Maitake mushrooms, Wagyu beef, foie gras, shaved black truffles, caviar and Japanese mayonnaise. Maille can at least claim that its ridiculously-priced offering has the benefit of simplicity.