1 stick (1/2 cup) unsalted butter, at room temperature
3/4 cup firmly-packed dark brown sugar
3/4 cup heavy cream (36% fat)
1/3 cup pure maple syrup (organic, if possible)
1/2 teaspoon kosher salt
1 teaspoon pure vanilla extract
8 ounces pecan halves (about 2 1/4 cups), lightly toasted
1 cup firmly-packed dark brown sugar (8 ounces)
1 tablespoon ground cinnamon
1/4 teaspoon kosher salt
Pinch cayenne pepper, optional
One 16-ounce package frozen puff pastry (two 8-ounce sheets per box, each 9 1/2-by-9 1/2 inches) or homemade, thawed overnight in the refrigerator
All-purpose flour, plus more for dusting
1 large egg white, lightly beaten