Preheat the oven to 350 degrees F.
In a large, heavy skillet melt 3 tablespoons of the butter over medium-high heat. Add the sugar, 1/2 cup of the brown sugar, the lemon juice and 1 tablespoon of the flour. Stir the mixture for 1 minute to dissolve the sugars. Add the apples and cook, stirring, for 3 minutes. Stir in the pecans and cook for 1 minute. Add the Calvados and carefully flambé the mixture off the heat. Return the pan to the heat and cook for an additional minute, then stir in the nutmeg, cinnamon, and pinch of salt. Mix thoroughly and remove from the heat to cool.
In a large mixing bowl, combine the remaining 4 tablespoons butter, the remaining 1/2 cup brown sugar, the remaining 1 cup of flour and the remaining pinch of salt. Blend the mixture well with your hands until it resembles coarse crumbs.
Roll out the pie shell and place in the bottom of a 10-inch pie pan, trimming the edges as necessary. Pour the apple filling into the pie shell and sprinkle the crumb topping evenly over the top. Place the pan in the preheated oven and bake until the top is lightly browned, about 45 minutes to 1 hour.
Remove the cobbler from the oven and serve warm topped with vanilla ice cream, if desired.
Yield: 1 10-inch cobbler, about 6 - 8 servings