I referred to the fantastic Dairy Book of Home Cookery (1968 version!) for the quantities of milk and eggs for their Quiche Lorraine. This said 3 eggs to quarter pint of milk and quarter pint of cream. I have never made quiche with cream, as I've never felt the need. I like it without the need for the extra creaminess and added fat, so half a pint of milk it was.
I also added another egg, as they were of medium size and I thought that it would add to the setting and aid the holding together - since there is no crust and it is not actually a frittata! I added about a half teaspoon of nutmeg and some pepper to the egg mixture before pouring it all on.
This was then put in the oven at 180C for about 45 mins, or until the egg was set. The Quiche Lorriaine recipe had all sorts of temperatures and timings, but the pastry wasn't baked blind. So I just kept testing it til it was set.
The result was a tasty Fritatta type thing which I've eaten every day for lunch with salad. The base was a bit watery, but this could be from the spinach, maybe I'll use raw next time to see what happens. I will definitely be making this again, perhaps with different ingredients.