1 1/2 cups (185 g/6 oz) plain flour
90g (3 oz) cold butter, chopped
1 egg yolk
20g (3/4 oz) butter
1 onion, chopped
4 rashers bacon, cut into thin strips
2 tablespoons chopped chives
3/4 cup (185 ml/6 fl oz) cream
1/4 cup (60 ml/2 fl oz) milk
100g (3 1/2 oz) Swiss cheese, grated
1. Place the flour and butter in a food processor and combine for 15 seconds, or until crumbly. Add the egg yolk and 2-3 tablespoons of water. Process in short bursts until the mixture just comes together. Add a little extra water if needed. Turn the mixture out onto a floured surface and gather together into a ball. Cover with plastic wrap and refrigerate for at least 15 minutes.
2. Roll the pastry between two sheets of baking paper until it is large enough to fit and overlap a shallow loose-based round flan tin measuring 25 cm (10 inches) across the base. Lift the pastry into the tin and press it well into the sides. Trim off any excess pastry using a sharp knife or by rolling the rolling pin across the top of the tin. Place the pastry-lined flan tin in the refrigerator for 20 minutes. Preheat the oven to moderately hot 190Â°C (375Â°F/Gas 5).
3. Cover the pastry shell with baking paper, fill evenly with baking beads and bake for 15 minutes. Remove the paper and beads and bake for a further 10 minutes, or until the pastry has dried out. Reduce the oven to moderate 180Â°C (350Â°F/Gas 4).
4. To make the filling, heat the butter in a heavy-based pan. Add the onion and bacon and cook for 10 minutes, stirring frequently, until the onion is soft and the bacon is cooked. Stir through the chives and set aside to allow to cool.
5. Beat the eggs, cream and milk together in a jug. Season with freshly ground black pepper. Spread the onion and bacon mixture evenly over the base of the pastry shell. Pour the egg mixture over the onion and bacon and sprinkle with the cheese. Bake for 30 minutes, or until the filling has set and the top is golden.