1 3/4 cups all-purpose flour
1/3 cup granulated sugar
1/4 tsp salt
1 stick butter, cold and cut into pieces
2 tbsp whipping cream
1 large egg yolk
Blend the flour, sugar, and salt together in a food processor. Add the butter to the processor; pulse until mixture resembles coarse meal. In a small bowl, whisk the cream and egg yolk together using a wire whisk. Add the cream/egg mixture to the processor and blend or pulse until moist clumps form. Using your hands, gather the dough into a ball and flatten into a disk. Wrap in plastic wrap and chill for an hour. (Dough can be made up to a day ahead and refrigerated. Let slightly soften at room temperature before trying to roll out.)
On a lightly floured surface, roll out the dough to a 14-inch circle. Transfer dough to a 9-inch tart pan that has a removable bottom. Press the dough firmly onto the bottom and up the sides of the pan. Pierce overall with a fork and freeze until firm; about 12 to 15 minutes.
Preheat oven to 350 degrees while the dough is in freezer. Line the crust with foil and fill with dried beans or use pie weights. Bake crust about 30 to 35 minutes at 350 degrees or until the sides are set and light golden in color. Remove foil with beans or the pie weights and bake about 15 minutes longer until the bottom is lightly browned and cooked through. Cool in pan on a wire rack. Do not turn oven off!
6 tbsp butter
3/4 cup packed brown sugar
1/2 cup whipping cream
4 large egg yolks (save 2 whites)
2 tbsp all-purpose flour
1 tsp vanilla extract
2 large egg whites, room temperature
1/4 tsp salt
1 1/4 cups coarsely chopped toasted pecans, divided
Cook the butter in a small heavy skillet over medium-high heat until it begins to brown. This should take about 2 to 3 minutes. Add the brown sugar and cream; bring to a boil while whisking to blend. Boil mixture for a minute. Transfer the mixture to a medium bowl and allow to cool until lukewarm; stir occasionally. This should take approximately a half hour.
Whisk the egg yolks and flour together in another medium bowl until blendeded. Whisk in the vanilla extract. Gradually add this mixture to the lukewarm butterscotch mixture whisking until smooth.
Beat egg whites and salt with an electric mixer until soft peaks (curl under when mixer beaters are removed). Fold half the mixture into the butterscotch mixer until blended. Fold in the remaining egg whites until just blended.
Spread a cup of the pecans evenly over the bottom of the crust. Gently pour the filling evenly over the pecans. Sprinkle the remaining pecans over the top of the filling.
Bake at 350 degrees until set and a deep brown color. This will take 25 to 30 minutes (do not overbake). Cool in the pan for at least two hours before removing from the pan.
To serve: Remove the sides from the tart pan. Cut tart into 10 servings and top each serving with whipped cream.