Step 1Place the flour, salt, nutmeg and lemon zest in a food processor and pulse to combine. Cut the butter into 1-inch cubes and add the cubes to the flour, pulsing 4 to 6 times to break up the butter.
Step 2Combine the vinegar and egg yolk in a measuring cup and add enough ice water to bring the volume up to one-half cup. Add the liquid in a steady stream to the food processor, while pulsing, until the flour looks crumbly and damp, 25 to 30 pulses. The crumbs should adhere when you gather them together with your fingers.
Step 3Turn the dough out and divide into two equal pieces. Wrap each in plastic wrap and press into a disk; refrigerate for 30 minutes to 1 hour.
Step 4Roll out one piece into a 12-inch circle, one-eighth-inch thick. Trim the edges flush with the rim of a 9-inch pie pan, place the dough circle into the pan and gently press the bottom and sides to fit. Roll out the other piece to a one-eighth-inch thickness and cut leaf shapes out of it. The leaves can be cut using a leaf-shaped cutter, or by hand using a stencil (ours was 1 inch by 3 inches) and paring knife. Using the back of a dinner knife, press a pattern into each leaf: Press one crease down the center, and 5 or so on each side of the crease. Mix a little water into the reserved egg white and, using a pastry brush, brush a little of the mixture around the edge of the pie crust. Press the leaves around the edge of the crust, overlapping them slightly and using the wash to adhere them, then brush the assembled crust with the wash. Freeze the pie crust for at least several hours and up to overnight.
Step 1Heat the oven to 450 degrees. In a mixing bowl, whisk together the pumpkin puree, cream, milk, eggs, egg yolk, Armagnac, light brown sugar, white pepper, cloves, cinnamon, allspice and cardamom until blended. Pour the mixture into the frozen pie shell and bake for 15 minutes, turning once for even browning. After 15 minutes, reduce heat to 350 degrees and continue to bake 25 to 30 minutes more, rotating again. Remove and let cool until room temperature. Chill overnight.
Step 2Just before serving, carefully fold strips of aluminum foil over the leaf-covered edges of the pie, being sure not to cover the custard. Scatter the superfine sugar evenly over the top of the pie and brulee under a hot broiler until the sugar caramelizes. (Or use a brulee torch if you have one.) Serve immediately, with a dollop of cardamom chantilly cream and candied lemon peel.
Step 1Place the lemon peel, sugar and 1 cup water into a small, heavy-bottomed sauce pan. Bring to a boil and then simmer over medium-low heat for 20 minutes. Remove the candied peel from the syrup with a slotted spoon and allow to cool on wax paper. (Save the lemon simple syrup for another use.)
Step 1Whip the cream, sugar and cardamom until gentle peaks form, and refrigerate.