Petit Pois Bistro, Hoxton square ★★★★★

In a nutshell: An ambitious French bistro in the achingly trendy Hoxton

The welcome: Petit Pois Bistro is right above its older sibling, Happiness Forgets, which has already made quite a name for itself as a hidden underground bar with killer cocktails. The usual hipster Hoxton crowd hadn't quite made it upstairs to Petit Pois when we visited, but the place had barely been open a week.

The room: It's an intimate affair with just 25 seats, bistro-style leather booths and marble-topped tables, a small patio out front and a well-stocked bar.

The atmosphere lacks the pizzazz that is sure to come when the space fills up with the stains of good memories.

The food: There's a small menu (definitely a good sign), with the usual bistro fare (steak frites, moules mariniere), plus a few surprises – some good and some, not so much.

The sea bream is complemented with a tomato beurre blanc, an ambitious touch which makes this a really special dish.

There are a few teething problems in the details: improperly cleaned mussels which were a little overpowered by the butter-heavy sauce, dry duck confit, and a lemon financier that had some inventive additions but missed out on the signature springy financier texture.

But there are some real treats: Anyone who tastes the chocolate mousse can die happy: tinged with a drop of orange liqueur, it was served so charmingly straight from the bowl at our table. The star is the dauphinois, with potatoes that melt into butter on the tongue.

We were recommended the Carignan to drink – a peppy red that happily accompanied our choices of both meat and fish.

Would we go again? Yes, especially for the life-changing chocolate mousse, but in a few months when the details have been ironed out and the space feels a bit more lived in.