This tasty dish is a variation on the classic Swedish potato gratin. Food writer John Duxbury shares his recipe.
This gratin is very easy to make and reheats well. The celeriac adds a little bite to a traditional potatisgratäng.
Preparation time: 10 minutes
Cooking time: 30 minutes
1 tbsp butter
350 g (12 oz) potatoes, peeled
200 g (7 oz) celeriac, peeled
salt and freshly ground black pepper