World’s first potato-chip sandwich café

Crisps—otherwise known as potato chips—aren't just for snacking anymore. The world's first "crisp sandwich" café opened, where customers can gorge on sandwiches made out of something different from the regular ham and cheese.

Inspired by an article on parody news website The Ulster Fry, Simply Crispy in Belfast, Northern Ireland opened its doors on Monday.

The pop-up café has already proven successful, having sold out of the crisp sandwiches only two hours after opening.

Tweet: Much love, guys xx we've sold out of everything now. I'll try and reply to all tonight. Thanks A xx

The shop offers 35 flavors of crisps, from the British favorites prawn cocktail and cheese and onion, to more niche brands like "Space Invaders."

The sandwiches can also come with ham and cheese, or with a side of soup and chips (fries).

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Will Simply Crispy last?

Cathal McNaughton | Simply Crispy Cafe | Reuters Pictures

Cafes like Simply Crispy that cater to customers with unusual taste buds may sound hip initially, but will they last?

Last December, the U.K.'s first cereal café, Cereal Killer Cafe, raised eyebrows when it launched with around 120 brands of cereal on offer.

However that wasn't the main question on people's minds—in an interview with the U.K.'s "Channel 4 News", café owner Gary Keery was questioned as to the rationale behind selling a small bowl of cereal for £2.50 ($3.80) in one of London's poorest boroughs.

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Entrepreneur Brothers Alan and Gary Keery | CerealKillerCafe.com

Cafes like Simply Crispy and Cereal Killer Cafe can last, however the novelty factor is an "important aspect in the initial popularity of these stores, as is the location," Karla Rendle, research analyst at Euromonitor International, told CNBC via email.

Rendle added that the fact that pop-up cafés may only be open for a limited time "adds to the novel experience, which combined with the right social media attention can generate a 'buzz' that may not be sustainable, but attracts a much higher level of interest."

However, permanent cafes like London's cereal café "will have to gain a loyal following to remain afloat," and make sure they maintain it.

"Crisp sandwiches represent the alternative or the 'anti-pret' offering to the chained bakery fast food industry. Some consumers might think it is a gimmick, others the return of no-nonsense food," said Rendle.

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Health concerns

Crisps are popular amongst Brits according to market research firm Mintel, which found that 92 percent of U.K. adults surveyed had eaten crisps and other savory snacks within the last three months.

However, crisps are high in saturated fats and salts and have been subject to a high-profile campaign by the British Heart Foundation to discourage over-consumption. The charity's "Food4Thought" campaign in 2006 revealed that half of U.K. children ate a packet of crisps per day, which was compared to drinking nearly five liters of oil every year.

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However, crisps' negative limelight may be starting to dim.

"Crisps have been seen to be getting a 'bad rap' over recent years, however, our latest research shows only 31 percent of Brits think crisps are unhealthy," Richard Ford, senior food and drink analyst, at Mintel, told CNBC via phone.

Some crisp brands have launched "healthier variants" that could have contributed to this result, added Ford.

"Around one in five Brits said they'd consider using standard potato crisps as an alternative to other ingredients in recipes, such as using them as croutons in salads," said Ford.