Preparation time: 15 minutes
Cooking time: 1 hour
Oven temperature: 230°C / 450°F
 

1. Peel the onions and slice them thinly.
2. Melt the butter in a skillet. Add the onions and sweat for 20-30 minutes over low heat - they should become very soft without browning.
3. Combine the eggs and cream in a bowl and mix in the onions. Season with salt, pepper and nutmeg.
4. Roll the pastry out and lay it in a buttered pie or cake pan. Prick all over with a fork. Pour the onion mixture into the pastry. Bake in a preheated 230° C (450°­ F) oven for 20-30 minutes.