Peel and coarsely grate the potatoes, sprinkle with salt and let sit for 15 minutes.

Squeeze excess moisture from the potatoes, grease the quiche tin, and press potatoes into the tin.

Preheat oven to 200°C (400°F) and bake crust for 20 minutes until golden, brush with egg white, and bake for another 3 minutes.

In a bowl, whisk together eggs and heavy cream, then add Gruyère, feta, capsicum, spinach, olives, sun-dried tomatoes, oregano, and pepper.

Pour filling into the crust, reduce oven to 180°C (350°F) and bake for 25–35 minutes until set with a jiggle.

Let quiche rest for 60 minutes before slicing and serve warm or at room temperature.