For the crust:
5 1/2 ounces all-purpose flour (approximately 1 1/4 cups)
4 1/2 ounces cake flour (approximately 1 cup)
6 tablespoons light brown sugar
1/2 teaspoon salt
8 ounces (16 tablespoons) good-quality unsalted butter, melted
1 teaspoon vanilla bean paste or vanilla extract

For the filling:
4 ounces (8 tablespoons) unsalted butter
1/2 cup packed light brown sugar
1/2 cup pure maple syrup, preferably grade B
2 tablespoons creme fraiche or heavy cream
1 teaspoon vanilla bean paste or vanilla extract
Pinch of salt
12 ounces chopped pecans (about 3 cups)