Pastry

Ingredients Grams Baker's % 
All-purpose flour 85.3 100 
Unsalted butter 70  82.4
Egg yolk 14.2  16.6

 

Filling

Ingredients Grams True %
Extra virgin olive oil 14  1.8
Onion, finely chopped 110  14.5
Sea salt as needed - 
Garlic cloves 6  0.8
Rosemary few sprigs  -
Swiss chard 255  33.6
Gruyere cheese, grated 142  18.7
Ground black pepper 142  18.7
Heavy whipping cream as needed  -
Large eggs 90  11.9

 

Preparation

For the pastry, rub the flour and butter together until the mixture forms fine crumbs. Swiss Chard and Gruyère Tart

Lightly beat the egg yolk with 1 tablespoon of cold water. Swiss Chard and Gruyère Tart

Add to the crumbs and bring together to form a soft dough. Add extra water if too dry. Swiss Chard and Gruyère Tart

Wrap in plastic wrap and chill for 1 hour. Preheat the oven to 350°F (180°C). Swiss Chard and Gruyère Tart

On a floured work surface, roll the pastry out to a large circle around 1/8in (3mm) thick. Swiss Chard and Gruyère Tart

Lift the pastry carefully, using the rolling pin to help you, and place it into the tart pan. Swiss Chard and Gruyère Tart

Push it in with your fingers. The pastry should overlap the sides by at least 3/4in (2cm). Swiss Chard and Gruyère Tart

Prick the bottom all over with a fork and line with parchment paper. Swiss Chard and Gruyère Tart

Weigh the parchment down with baking beans. Place the pastry shell on a baking sheet. Swiss Chard and Gruyère Tart

Bake in the center of the oven for 20–25 minutes. Remove the beans and paper. Swiss Chard and Gruyère Tart

Bake for 5 more minutes to crisp the bottom. Leave to cool and trim the edges with a knife. Swiss Chard and Gruyère Tart

Meanwhile, heat the oil in a pan over low heat. Add the onion and a pinch of salt. Swiss Chard and Gruyère Tart

Cook the onion until soft. Add the garlic and rosemary and cook for a few seconds. Swiss Chard and Gruyère Tart

Coarsely chop the Swiss chard and add to the pan. Stir for about 5 minutes until it wilts. Swiss Chard and Gruyère Tart

Set the pastry shell on a baking sheet and spoon in the onion and chard mixture. Swiss Chard and Gruyère Tart

Sprinkle over the Gruyère cheese, and scatter with the feta. Season well. Swiss Chard and Gruyère Tart

With a fork, mix together the cream and the 2 eggs until well combined. Swiss Chard and Gruyère Tart

Carefully pour the cream and egg mix over the tart filling. Swiss Chard and Gruyère Tart

Bake for 30–40 minutes until golden. Leave to cool before releasing from the pan. Swiss Chard and Gruyère Tart

Serve warm or at room temperature. Best eaten the same day. Can be chilled overnight.