Quiche recipe

This is more so I remember than for you to follow. I always forget how much egg and milk I used last time to fill the dish I have.

400ml creamy milk (ideally Jersey!)
7 medium eggs
1 onion chopped and gently fried
Other filling eg mushrooms, ham, bacon, salmon (obvs not all together)
1 round puff pastry from the supermarket (or make your own)
Deepish quiche/pie dish 28cm

Put pastry in dish
Beat eggs and milk together with salt and pepper
Pour into the pastry
Add the onion, and other filling. Bake at 6 (which is about 170 on a normal oven) for 40 mins until set and brown