1. Preheat oven to 400 degrees. On a lightly floured surface, roll out dough to a 13-inch round, about 1/8 inch thick. Brush off excess flour; fit dough into a 9-inch pie plate. Trim to a 1/2-inch overhang. Tuck dough under, forming a rim; crimp as desired. Chill 30 minutes.

2. In a small bowl, whisk 1 egg and cream; set aside. Prick dough all over with a fork. Line with parchment; fill with pie weights or dried beans. Bake until edges begin to turn golden, about 10 minutes. Remove parchment and weights. Brush shell with egg wash, leaving rim uncoated. Continue baking until center is golden, 5 minutes more. Let cool on a wire rack.

3. Reduce oven heat to 350 degrees. Meanwhile, bring sugar and 1/2 cup water to a boil in a medium saucepan, stirring until sugar dissolves. Then without stirring, cook until caramel is light amber, about 7 minutes, washing down sides of pan with a wet pastry brush to prevent crystals from forming. Remove from heat; stir in creme fraiche (it will spatter). Let cool 5 to 10 minutes. If it starts to harden, place briefly over low heat, stirring constantly.

4. In a small bowl, whisk remaining 3 eggs; slowly whisk in 1 cup caramel. Whisk mixture back into remaining caramel in saucepan. Stir in nuts.

5. Pour filling into pie shell; bake until slightly puffy and set, about 30 to 40 minutes. Let cool on a wire rack.