Turnip gratin

Ingredients 500g (1lb) turnips 75g (3oz) unsalted butter 1 heaped tbsp plain flour 8 fl oz milk 1 egg yolk 125g (3oz) Gruyere cheese, grated salt and pepper to taste Method A recipe which brings out the flavour of turnips well, making a good filling vegetable dish. Around 500g (1lb) turnips are enough for two. Peel the turnips and slice into rounds. Blanch in boiling salted water for a minute, then drain and refresh under cold running water. Melt half the butter in a large saucepan or frying-pan and braise the turnip slices until just soft, then put into a buttered gratin dish. Pre-heat the oven to Gas Mark 6, 200 deg C, 400 deg F. Melt the rest of the butter in a non-stick milk pan, add the flour and stir until mixed. Slowly add the milk, stirring all the time until you have a smooth sauce. Add salt to taste with half the cheese and stir well. Remove from the heat and mix in the beaten egg yolk. Pour the sauce over the turnips, sprinkle with the rest of the grated cheese and brown in the pre-heated oven for 10 minutes, until the top is brown and bubbling.