Onion Tart

Ingredients

  • 900 g/ 2 lb onions, sliced
  • 60 g/ 2 oz butter
  • 60 g/ 2 oz flour
  • salt and pepper
  • freshly grated nutmeg to taste
  • 300 ml/ ½ pint milk
  • 3 eggs, separated

For the Shortcrust Pastry

  • 125 g/ oz plain flour
  • 75 g/ oz chilled unsalted
  • butter, cut into dice
  • 1 egg yolk
  • pinch of salt

Method

First make a shortcrust pastry by putting the flour in a food processor with the chilled butter dice. Whiz to a crumb consistency then add the egg yolk, salt and 1–2 tablespoons of cold water. Work briefly until it balls. Remove, cling-wrap and refrigerate for 1 hour.

Preheat the oven to 200°C/ 400°F/ gas 6. Roll the rested pastry out and use to line a 23-cm / 9-inch tart tin, with a double thickness round the edges, pricking the base and pinching the pastry up above the level of the tin to allow for shrinkage. Line with baking paper, weight with beans then bake blind for 10 minutes. Remove from the oven.

Sweat the onions in the butter until soft. Add the flour and cook for 2 minutes. Season with salt, pepper and nutmeg, and pour over the milk. Cook over a low heat for 20 minutes, stirring at regular intervals. Off the heat, beat the yolks into this mixture.

Whisk the egg whites until stiff and fold them into the onion custard. Spoon into the pastry shell, put into the oven, lower the temperature to 190°C/ 375°F/gas 5 and bake for 15–20 minutes, until golden and risen. Serve immediately.

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