Ask Italian has been fined £40,000 for a "misleading" description of one of their dishes.
The Aragosta e Gamberoni pasta dish is marketed as containing lobster and king prawns but an investigation found the dish only contained 35 per cent lobster.
34 per cent was made of white fish and the rest, other ingredients formed to look like lobster meat.
Ask Italian's parent company, Azzuri Restaurants Limited, admitted the charge at Swansea Magistrates' Court and apologised for the "error" it had made.
The pasta dish, one of their most expensive menu items, was sold for £14.95 throughout their UK restaurants.
The lack of lobster was spotted by a Swansea Council trading standards officer during a routine visit to a branch in the city in 2019.
The officer asked to see the original packaging and ingredients for the dish, which was described as containing "lobster and king prawns in a creamy tomato sauce with a hint of chilli".
The packaging produced was for a product called Lobster Sensations, which is a blend of real lobster and a lobster flavoured fish mix.
This mix contains 35 per cent real lobster with a similar amount of white fish and then other ingredients such as potato starch and soy protein.
Swansea Magistrates' Court heard consumers had been "misled" about the true nature of the dish but the company insisted it was a "labelling mistake" and there was no intention to deceive.
The dish was removed from menus after the council raised the issue.
The prosecution said customers ordering the dish did not get what they were "entitled to expect".
Whilst the dish sells for £14.95, the actual cost of the raw ingredients was £2.84, of which the mixed seafood product made up 70p.
The restaurant company apologised for the "error" it had made and said there had been no intention to mislead. They "strongly denied" there had been any financial motivation behind it.
District judge Neale Thomas said the way the dish had been described on the menu was a "deliberate action" and that it "falsely represented" the nature of the food.
Azzurri Restaurants Limited were fined £40,000 for the offence.