The "world's first" crisp sandwich shop has sold out within two hours of opening.
Simply Crispy in Belfast experienced overwhelming demand for Tayto cheese and onion flavour crisps inside the white floury Belfast bap.
The pop-up cafe offering 35 different flavours opened following a spoof suggestion by the Ulster Fry satirical website and came after the establishment of a cereal outlet in London.
Customer Nerys Coleman, 32, said: "It is something from your childhood. I have not had a crisp sandwich since university and before that childhood so it is bringing back the nostalgia."
Owner Andrew McMenamin said: "I have been told it is the world's first."
He said a Belfast bap and Tayto cheese and onion were the most popular choices.
"It is a school thing, people remember it from their school days, it is a classic and it is old-school."
Mr McMenamin, who owns That Wee Cafe, offered to transform his business when he read the spoof online.
It is expected to run for three or four weeks.
Customers were able to choose their bread, crisps and add cheese or ham to their sandwich, served with soup and chips.
Tayto provides most of the crisps "due to its large variety", but Walkers will also be represented.
Among the bread on offer were the traditional white Belfast bap, a large crusty round bread which can be split in the middle and stuffed with fillings.
Mr McMenamin added: "We are riding on the back of the publicity the cereal cafe got in London, if it helps us and Ulster Fry then it is a good thing."
The Cereal Killer Cafe opened in Brick Lane, London, last year and sells classics like Rice Krispies.
It was established by Belfast twins Alan and Gary Keery.
Mr McMenamin would not be drawn on the long-term prospects for his own novel venture.
"It is certainly play it by ear, hopefully it will rekindle childhood memories of Belfast baps."
The idea has been credited to comedy writer Seamus O'Shea and his writing partner Billy McWilliams, who run the Ulster Fry website.