- Half of the recipe for Flaky Pie Dough, click here for recipe
- Olive oil for frying, roasting and drizzling
- 1 large onion (12 ounces), thinly sliced
- ½ teaspoon finely chopped fresh thyme or rosemary
- Black pepper
- 115g Swiss Cheese (Emmental works well), coarsely grated
- 450g roasting potatoes, washed (left unpeeled) and cut into ¼-inch-thick slices
- 1 egg, lightly beaten
Preheat the oven to 200°C and position an oven rack in the lower third.
Line a baking sheet with parchment paper. Roll the dough into a large, thin round and transfer it to the baking sheet. Chill for 1 hour.
Roast the potatoes: drizzle a roasting tin with a little olive oil, season the potato slices with salt and pepper and place on tray in a single layer. Cook in a preheated oven for 20-25 minutes until fork tender. Take out of the oven and let cool completely.
Heat a small amount of olive oil in a medium sauté pan over medium-high heat.
Add the onion and cook, stirring occasionally, until soft and lightly coloured, 8 to 10 minutes. Stir in the thyme or rosemary, season with salt and pepper. Transfer to a plate and set aside to cool.
Combine the cooled onion mixture, cheese and roasted potatoes in the large bowl. Mound the filling in the centre of the chilled tart shell, leaving a 3cm border at the edge. Fold that border up around the filling, pleating it to make a pretty, circular enclosure and leaving the centre open.
Drizzle the filling with olive oil and sprinkle lightly with salt and pepper. Lightly brush the pleated dough with the beaten egg to give it shine and help it brown in the oven.
Bake the pie for 45 to 50 minutes, until the pastry is golden brown.
Use the metal spatula to lift the edge of the pie slightly and check underneath. The bottom crust should be a beautiful brown colour. Transfer to a rack to cool for 5 to 10 minutes.