Recipe: root vegetable gratin by Blanche Vaughan

I suggest making this comforting vegetable gratin the day before you plan to eat it, and then reheating and serving straight from the oven, said Blanche Vaughan. Like cooks and hosts, many dishes are more enjoyable when they've had some time to relax.

Ingredients: serves six

• 2 large Désirée or King Edward potatoes
• 2 large sweet potatoes 
• 1 large celeriac
• 3 large parsnips
• 100g butter, melted
• 2 tsp finely chopped rosemary leaves
• 250ml double cream
• 125ml chicken or vegetable stock
• 3 bay leaves
• 2 garlic cloves, crushed
• sea salt and freshly ground black pepper

Method

• Peel all the vegetables and rinse well with cold water. If you have a vegetable-slicing machine, this is its moment. Slice each vegetable and keep separate so that the colours are not mixed up. Alternatively, cut the potatoes, sweet potatoes and celeriac in half and slice across as thinly as possible by hand, with a sharp knife. The parsnips may be sliced across whole, in thin slices.
• Choose a large enough ovenproof dish and brush with half the melted butter. In a small bowl, mix the rosemary with 1 teaspoon of salt and 1 teaspoon of pepper. Start to fill the dish with the potato slices – they should be arranged in concentric circles so that they slightly overlap one another. Add a sprinkling of the rosemary mixture.
• Cover the potatoes with half the sweet potatoes in the same way; then the celeriac; then the remaining sweet potatoes; then the parsnips. This final layer should be arranged carefully, with beautifully overlapping slices, as this will top the finished dish.
• Preheat the oven to 180°C. In a saucepan, combine the cream, stock, bay leaves and garlic with half a teaspoon of salt and half a teaspoon of pepper. Heat until simmering. Remove the leaves and set aside. Gently pour the liquid over and around the sliced vegetables, allowing it to sink slowly into the dish before adding more. If you don’t need all the liquid, any leftovers could be used to top up the dish during cooking. Drizzle the rest of the melted butter over the top and garnish with the bay leaves.
• Place the dish on a baking sheet (as the cream may bubble over) and bake for 1 hour-1 hour 20 mins (10-15 mins on reheat). If the surface starts to colour too soon, cover with a piece of foil and continue to bake until a sharp knife pierces the centre easily. The top should be golden brown all over, with a few crisp, slightly burnt edges for colour. Remove the dish and serve, or cover tightly with foil until you are ready to serve.

Recipe from "House & Garden – A Year in the Kitchen: Seasonal recipes for everyday pleasure" by Blanche Vaughan, published by Mitchell Beazley at £35. To buy from The Week Bookshop for £27.99 (incl. p&p), visit theweekbookshop.co.uk. Sign up for The Week's Food & Drink newsletter for recipes, reviews and recommendations.