For the Pastry:

1 1/4 cups all-purpose flour
2 tablespoons granulated sugar
1/2 teaspoon salt
3 1/2 ounces (7 tablespoons) unsalted butter, cold
3 tablespoons cold water

For the Orange Filling:

4 ounces (8 tablespoons) unsalted butter
1/4 cup sour cream, or crème fraiche
2 large eggs
3 large egg yolks
2/3 cup granulated sugar
2/3 cup freshly squeezed orange juice
4 teaspoons orange zest

Make the Pastry

In a small bowl, mix the flour, sugar, and salt.

Using a pastry cutter, large-tined fork, or a food processor on pulse setting, cut the chilled butter into the flour until it resembles coarse sand with a few pea-sized pieces of butter still visible.

Sprinkle the cold water onto the mixture and toss a few times gently, just until it forms a ball that holds together.

Separate the dough into two balls, flatten slightly into thick disk shapes, wrap in plastic wrap, and chill for several hours before working with it.

Preheat an oven to 375 F. Roll and trim the dough to make a circle large enough to fit a 10-inch fluted tart pan. Fit the circle into the bottom and up the sides of the pan.

Line the dough with pie weights or dried beans and bake it for 15 minutes.

Remove the pie weights and bake the shell for an additional 5 minutes. Set aside the pastry shell, still in the tart pan, to cool.

Make the Orange Filling

Gather the ingredients.

In a double boiler or a medium-size saucepan set a large pan of simmering water, stir together 8 tablespoons butter and the crème fraiche. Once this mixture is thoroughly combined, set it aside.

In a separate pan set over the double boiler, whisk together the eggs, egg yolks, and sugar.

Stir the orange juice into the mixture and cook, constantly stirring for 3 minutes.

Add the orange zest and butter-crème fraiche mixture to the eggs and cook, constantly stirring for 3 minutes.

Reduce oven to 325F. Pour the orange filling into the prepared pastry and bake it for 25 to 30 minutes until it turns golden brown and the filling is set.

Allow the tart to cool in the pan on a wire rack for 15 minutes.

Serve at room temperature, or chill in the refrigerator before serving.

makes far too much pastry! could do it with just over half the quantities...