Sift the flour together with a pinch of salt in a large bowl. Rub in the butter until you have a soft breadcrumb texture.

Add the egg to make the ingredients stick together and form a firm dough, then rest in the refrigerator for 30 minutes.

Roll a large disk on a light floured surface and line a 27 cm/ 8.6 inch spring form. Prick with a fork and prebake the pie crust at 180°C (350°F) for 10-15 minutes.

Peel and finely chop the onion, then fry it with one tablespoon of butter on low heat until the onion has softened, about 5-8 minutes.

Fry the diced bacon in a frying pan for about 3 minutes.

Whisk together the eggs, milk and cream. Add the grated Emmental cheese. Season with salt and pepper.

Place the caramelized onions onto the pie crust and add the diced bacon. Pour the filling over and bake for 25 minutes at 180°C (350°F) in the lower part of the oven. The pie is done when the pie is golden and the filling has solidified.

Garnish with fresh parsley and serve the pie warm.