Quiche Aux Oignons (Onion Quiche)

from Mastering the Art of French Cooking, Volume 1, page 151

2 lbs minced onions (about 7 cups)
3 tbsp butter
3 tbsp oil
1 1/2 tbsp flour
2 eggs or 3 yolks
2/3 cup whipping cream
1 tsp salt
1/8 tsp pepper
Pinch of nutmeg
2 oz (1/2 cup) grated Swiss cheese
A 9 inch partially cooked pastry shell
1 tbsp butter cut into pea sized dots

Cook the onions in a heavy skillet with the oil and butter over very low heat, stirring occasionally until they are extremely tender and h a golden yellow.  This will take about an hour.

Sprinkle with the flour and mix well, cook slowly for 2 or 3 minutes. Allow to cool slightly.

Beat the eggs or egg yolks in a mixing bowl with the cream and seasonings until blended.  Gradually mix in the onions and half of the cheese.  Check seasoning.  Pour into tart shell.  Spread on the rest of the cheese and distribute the butter over it.  Bake in upper third of preheated oven for 25 to 30 minutes until quiche has puffed and golden brown.