Mary Berry gave a lesson to a novice cook in how to prepare a vegetable gratin for the festive season on Mary Berry Saves Christmas.

The ingredients are: butter, for greasing and frying, 4 banana shallots, thinly sliced lengthways, 350g carrots, peeled and sliced into thin batons, 850g potatoes (such as Maris Piper, Rooster or King Edward), peeled, 450ml vegetable stock, 300ml double cream, 75g Parmesan (or a similar vegetarian hard cheese), grated, 1 tbsp chopped fresh parsley, salt and pepper.

See Mary’s Christmas recipes in her book titled: Mary Berry’s Christmas Collection available from Amazon now.