English changes all the time and some recent changes have taken even native speakers by surprise.
Nobody has ever sold food labelled as simply ‘posh’ and meant it; usually ‘posh’ is used by people who are not ‘posh’ to label something as pretentious or overly fancy. ‘Posh’ things were for rich people who showed off what they had. Nowadays, however, young rich people in Brooklyn, New York and Shoreditch, London want to show off how cultured they are.
You can get craft beer, craft cider (an alcoholic beverage made using apples or, occasionally, pears) and such. It means that the brewery uses old fashioned methods which are expensive and the beer usually tastes better. Sometimes it tastes better, sometimes it doesn’t.
An artisan is an expert craftsman, usually one who spends a long time making complex works. When it comes to food, artisanal bakeries sell decorative cakes that use fancy ingredients.
There are, apparently, artisanal toast cafés in London now, but this may be just a rumour.
This one is less popular with cool young people but is often seen describing foreign foods, for example:
Authentic Indian Cuisine; Authentic Italian Panini;
Authentic French Bakery.
‘Authentic’ just means ‘real’.