Step 1 Cut the butter into slices (8-10 slices per stick). Put the butter in a bowl and place in the freezer. Fill a medium-sized measuring cup up with water, and add plenty of ice. Let both the butter and the ice sit for 5-10 minutes.
Step 2 In the bowl of a standing mixer fitted with a paddle attachment, combine the flour, sugar, and salt. Add half of the chilled butter and mix on low, until the butter is just starting to break down, about a minute. Add the rest of the butter and continue mixing, until the butter is broken down and in various sizes (some butter will be incorporated into the dough, some will still be a bit large, but most should be about the size of small peas). Stop the mixer and use your hands to check for any large pieces of butter that didn’t get mixed or any dry patches of dough on the bottom of the bowl; break up the butter and incorporate the dry pieces as best you can. Slowly add the water, a few tablespoons at a time, and mix until the dough starts to come together but still is quite shaggy (if the dough is not coming together, add more water 1 tablespoon at a time until it does).
Step 3 Dump the dough out on your work surface and flatten it slightly into a square. Gather any loose/dry pieces that won’t stick into the square and place them on top. Gently fold the dough over onto itself and flatten again. Repeat this process 3 or 4 more times, until all the loose pieces are worked into the dough. Be very gentle with your movements, being careful not to overwork the dough. Flatten the dough one last time into a circle, and wrap in plastic wrap. Refrigerate for 30 minutes (and up to 2 days) before using.
Step 4 Adjust oven rack to lowest position, place rimmed baking sheet on rack, and heat oven to 400°F. Remove dough from refrigerator and roll out on generously floured (up to 1/4 cup) work surface to 12-inch circle about 1/8 inch thick. Roll dough loosely around rolling pin and unroll into pie plate, leaving at least 1-inch overhang on each side. Working around circumference, ease dough into plate by gently lifting edge of dough with one hand while pressing into plate bottom with other hand.
Step 5 Trim overhang to 1/2 inch beyond lip of 9-inch pie plate. Fold overhang under itself; folded edge should be flush with edge of pie plate. Using thumb and forefinger, flute edge of dough. Freeze dough for 20 minutes while the oven preheats. Remove pie pan from the freezer, line crust with foil, and fill with pie weights or pennies. Bake on rimmed baking sheet 15 minutes. Remove foil and weights, rotate plate, and bake 5 to 10 additional minutes until crust is golden brown and crisp. Remove pie plate and baking sheet from oven. Let cool only slightly before filling with pumpkin pie filling.
Step 6 Preheat oven to 400F. While the pie shell is baking (see recipe below), whisk cream, milk, crème fraîche, eggs, yolks, and vanilla together in medium bowl. Combine pumpkin puree, sugars, maple syrup, cinnamon, ginger, nutmeg, and salt in large heavy-bottomed saucepan; bring to sputtering simmer over medium heat, 5 to 7 minutes. Continue to simmer pumpkin mixture, stirring constantly until thick and shiny, 10 to 15 minutes.
Step 7 Remove pan from heat and stir in the black strap rum if using. Whisk in cream mixture until fully incorporated. Strain the mixture through fine-mesh strainer set over a medium bowl, using a spatula to press the solids through the strainer. Re-whisk the mixture and transfer to warm pre-baked pie shell. Return the pie plate with baking sheet to the oven and bake pie for 10 minutes. Reduce the heat to 300°F and continue baking until the edges of the pie are set and slightly puffed, and the center jiggles only slightly, 27 to 35 minutes longer (see notes below). Transfer the pie to wire rack and cool to room temperature, 2 to 3 hours (it can also be refrigerated for several hours before serving). Cut into wedges and serve with whipped cream.
