For Sugared Cranberries (Day Before): Simmer water and 3/4 cup sugar until dissolved. Pour over cranberries. Soak 15 min, drain, dry 1 hour. Toss in remaining 1/2 cup sugar. Dry 1 more hour. Refrigerate.
Prepare Crust: Make pie dough. Divide in two, shape into discs, wrap, and chill for at least 2 hours.
Par Bake Crust: Preheat oven to 375°F (190°C). Roll one dough disc to a 12 inch circle. Fit into a 9 inch deep dish pie plate. Crimp edges. Line with parchment, fill with pie weights. Bake 10 min. Remove weights/parchment, prick bottom with fork, bake 7-8 more min until starting to brown. Brush warm edges with egg wash.
Make Filling: Whisk pumpkin, 3 eggs, and brown sugar until smooth. Whisk in cornstarch, salt, spices, cream, and milk until completely combined.
Bake: Pour filling into warm crust. Bake 25 min, then cover crust edges with foil. Bake 30-35 more min (55-60 min total) until edges are set and center wobbles slightly.
Cool: Cool pie completely on a wire rack for at least 3-4 hours to set.
Serve: Garnish with sugared cranberries and whipped cream. Slice and enjoy.