Mary Berry's Christmas vegetable gratin recipe
 Mary Berry’s vegetable gratin brings potatoes and carrots together in a dish that’s rich, creamy, colourful and full of flavour. butter, for greasing and frying4 banana shallots, thinly sliced lengthways350g/12oz carrots, peeled and sliced into thin batons 850g/1lb 14oz potatoes (such as Maris Piper, Rooster or King Edward), peeled450ml/16fl oz vegetable stock 300ml/½ pint double cream 75g/2½oz Parmesan (or a similar vegetarian hard cheese), grated 1 tbsp chopped fresh parsleysalt and freshly ground black pepper butter, for greasing and frying 4 banana shallots, thinly sliced lengthways 350g/12oz carrots, peeled and sliced into thin batons 850g/1lb 14oz potatoes (such as Maris Piper, Rooster or King Edward), peeled 450ml/16fl oz vegetable stock 300ml/½ pint double cream 75g/2½oz Parmesan (or a similar vegetarian hard cheese), grated 1 tbsp chopped fresh parsley salt and freshly ground black pepper Method Preheat the oven to 200C/180C Fan/Gas 6. Butter a 1.7–2 litre/3–3½ pint wide ovenproof dish. Melt a knob of butter in a frying pan, add the shallots and fry for about 5 minutes until soft. Add the carrots and stir together for 30 seconds. Spoon into the buttered dish. Season with salt and pepper.Thinly slice the potatoes into discs about the thickness of a £1 coin. Pour a third of the stock and a third of the cream over the carrots and shallots. Arrange half the potatoes on top. Season and pour over another third of the stock and cream. Push the vegetables down into the liquid. Arrange the remaining potatoes in neat overlapping rows over the top. Season and pour over the remaining stock and cream. Push down, then sprinkle over the cheese. Cover the dish with foil.Bake for about 30 minutes, until the potatoes around the edge of the dish are soft. Remove the foil and cook for a further 25 minutes, or until all the vegetables are cooked through and the top is golden-brown. Scatter over the parsley to serve. Preheat the oven to 200C/180C Fan/Gas 6. Butter a 1.7–2 litre/3–3½ pint wide ovenproof dish. Preheat the oven to 200C/180C Fan/Gas 6. Butter a 1.7–2 litre/3–3½ pint wide ovenproof dish. Melt a knob of butter in a frying pan, add the shallots and fry for about 5 minutes until soft. Add the carrots and stir together for 30 seconds. Spoon into the buttered dish. Season with salt and pepper. Melt a knob of butter in a frying pan, add the shallots and fry for about 5 minutes until soft. Add the carrots and stir together for 30 seconds. Spoon into the buttered dish. Season with salt and pepper. Thinly slice the potatoes into discs about the thickness of a £1 coin. Thinly slice the potatoes into discs about the thickness of a £1 coin. Pour a third of the stock and a third of the cream over the carrots and shallots. Arrange half the potatoes on top. Season and pour over another third of the stock and cream. Push the vegetables down into the liquid. Arrange the remaining potatoes in neat overlapping rows over the top. Season and pour over the remaining stock and cream. Push down, then sprinkle over the cheese. Cover the dish with foil. Pour a third of the stock and a third of the cream over the carrots and shallots. Arrange half the potatoes on top. Season and pour over another third of the stock and cream. Push the vegetables down into the liquid. Arrange the remaining potatoes in neat overlapping rows over the top. Season and pour over the remaining stock and cream. Push down, then sprinkle over the cheese. Cover the dish with foil. Bake for about 30 minutes, until the potatoes around the edge of the dish are soft. Remove the foil and cook for a further 25 minutes, or until all the vegetables are cooked through and the top is golden-brown. Scatter over the parsley to serve. Bake for about 30 minutes, until the potatoes around the edge of the dish are soft. Remove the foil and cook for a further 25 minutes, or until all the vegetables are cooked through and the top is golden-brown. Scatter over the parsley to serve.