While it is the perfect antidote to a long day pushing past grey faces on Princes Street, the Mussel Inn is not the restaurant to celebrate a special occasion in, its dining room a bland sweep of plain walls and plainer furniture. The only decor that is not completely forgettable is a large fish mosaic, which unfortunately hints at up-market chippy, rather than the award-winning restaurant that it is.

Yet this Rose Street joint's reputation for simply cooked, fresh fish is as strong as ever. There is a good range of seafood served, from smoked salmon to oysters. I was immediately enraptured by the huge, steaming pots of mussels quickly brought out in healthy kilos and half-kilos. There is a reasonable range of sauces to choose from, although I found the mature blue cheese addition made for an odd pairing with the poor man's shellfish.

I opted for a traditional shallot and white wine dressing, letting the rich flavour of the mussels come through. That unmistakable, sweet flavour was all that was needed to evoke happy memories of childhood holidays spent on the beaches of Brittany. While the obligatory crusty bread was more Delice de France than crisp French baguette, at just £5.65 for half a kilo of naturally selected Scottish mussels, this was a small complaint. The quality of the baguette is telling – the kitchen's expertise does not lie in boulangerie. Stick to the fish.

The pasta with wild mushrooms, spinach, and fettuccini with lemon and mascarpone cheese sounded delicious on the menu. On the plate, the pasta floundered, an insipid mess devoid of any depth.

Unsurprisingly, the wine menu features an abundance of whites. We opted for the crisp Paul Bouchard, priced at £14.50, which naturally went well with the fish.

The lunch menu is excellently priced, at £7.50 for a bowl of mussels or seafood chowder with salad or fries, accompanied by beer, a glass of wine, or a soft drink. This deal runs until 3pm on weekdays, and 5pm on a Friday. The restaurant also offers a “catch of the day” which is a fish dish based on what the suppliers have caught an abundance of that day.

With such simple, fresh produce on offer, the Mussel Inn is bound to flourish as much as its aquatic namesakes in the cold seasons.