INGREDIENTS
•
Dough
•
1 cup all-purpose flour
•
1/4 teaspoon salt
•
6 tablespoons unsalted butter, cut into small pieces and chilled
•
5 tablespoons ice cold water
•
Filling
•
4 tablespoons unsalted butter
•
2 1/2 pounds sweet onions, thinly sliced
•
6 thyme sprigs
•
2 tablespoons crème fraîche
•
Salt and freshly ground pepper
•
1 egg beaten with 1 tablespoon of milk