If using, begin at least a day ahead. In a medium saucepan, simmer water and 3/4 cup (150g) sugar until dissolved, remove from heat and cool 5 minutes. Pour syrup over cranberries in a heatproof bowl, cover and let sit 15 minutes. Transfer cranberries to a parchment-lined sheet to dry for 1 hour, then toss in remaining sugar and dry again for at least 1 hour. Refrigerate up to 3 days.

Roll chilled pie dough into a 12-inch circle on a floured surface. Fit into a 9×2-inch deep-dish pie dish, trim and crimp edges. Lightly brush edges with egg wash. Chill crust while preparing filling.

Preheat oven to 375°F (190°C). Line crust with parchment and fill with pie weights or dried beans. Bake 10 minutes. Remove parchment and weights, prick bottom with a fork, and bake 7-8 minutes more until lightly browned.

In a large bowl whisk pumpkin puree, eggs, and brown sugar until blended. Add cornstarch, salt, cinnamon, ginger, nutmeg, cloves, and pepper. Whisk in heavy cream and milk until smooth.

Pour filling into warm, par-baked crust about 3/4 full. Bake 55-60 minutes until center is almost set; it may wobble slightly. After 25 minutes, shield crust edges with foil or a crust shield to prevent over-browning. Check doneness around 50 minutes.

Cool pie on a wire rack for at least 3 hours before slicing. Decorate with sugared cranberries and pie crust leaves if using. Serve with whipped cream if desired.