Chard, caramelised onion and goats’ cheese tart

1. Preheat the oven to 190˚C, gas mark 5. Roll the pastry sheet out a little thinner and use to line a 23cm, deep tart tin with a removable base, leaving the excess pastry overhanging the edge. Prick the base all over with a fork, place on a baking sheet and chill for 30 minutes.

2. Line the pastry case with baking parchment and baking beans and bake for 15 minutes. Remove the parchment and beans and bake for another 10 minutes, until very pale gold and sandy-looking. Gently brush the hot base of the pastry case with the egg white to seal. Leave to cool, then trim off the excess pastry.

3. In a pan, fry the onion and a pinch of salt in the oil and butter over a medium heat for about 5 minutes, stirring often. Reduce the heat, cover and continue to cook, stirring occasionally, for 20 minutes. Turn the heat up and add the chard stalks, balsamic vinegar and ½ tbsp thyme leaves. Once the onion is browned and sticky, stir in the chard leaves and cook down for 2 minutes, until wilted.

4. Spread the onion and chard mixture out in the pastry case; top with the goats’ cheese. Whisk together the nutmeg, cream, 2 whole eggs and remaining yolk; season. Pour into the case, scatter with the remaining thyme leaves and bake for 30 minutes, until puffed, golden and just set. Leave to cool before serving