Chard, caramelised onion & feta tart

1. Roll out the pastry a little thinner and use to line a 24cm, deep tart tin with a removable base. Set the tin on a baking sheet, leaving the excess pastry overhanging the edges. Prick the base all over with a fork and chill for 30 minutes. Preheat the oven to 190˚C, gas mark 5.

2. Meanwhile, heat the oil in a pan. When hot, add the onions with a pinch of salt and a generous amount of black pepper. Cook for 10 minutes over a medium heat, stirring regularly. Once the onions have some colour, turn the heat down to low, cover and cook for another 10 minutes. Lift the lid and stir occasionally so the onions caramelise without burning. Remove from the heat and allow to cool completely. 

3. Bring a large pan of salted water to the boil. Trim the chard stalks and separate them from the leaves. Slice the stalks into 1cm lengths and cut the leaves into ribbons. Add the stalks to the boiling water, cook for 5 minutes, then add the leaves and cook for a further 2-3 minutes. Drain, then leave in the colander to cool. 

4. When the pastry has chilled, line the pastry case with baking parchment, fill with baking beans and blind-bake for 15 minutes. Remove the parchment and beans and bake for another 10 minutes, until pale gold and sandy to the touch. Gently brush the base of the hot pastry case with the egg white to seal and leave to cool. Turn the oven down to 170˚C, gas mark 3.

5. Squeeze out the excess liquid from the chard with your hands. In a bowl, combine the cooled chard, pine nuts, chilli flakes, olives and feta and mix together, using your hands. Spread ½ the cooled onions across the base of the tart, then top with ½ the chard mixture. Whisk the cream, 2 eggs and the remaining yolk together in a jug or bowl; season and pour ½ into the case. Repeat with the remaining ingredients. Bake for 30-40 minutes, until golden and just set. Trim off the excess pastry and allow to cool a little before slicing. Serve the tart straight away or at room temperature.