Bake entire pumpkin at 350 degrees for 20 minutes, or just until skin softens enough to cut easily. Remove from oven and cool until handle-able. Cut skin off, cut into manageable chunks and remove seeds. Place skinned and seeded pieces on parchment-lined baking pan and return to oven. Bake until pumpkin is very soft, 30-45 minutes. Remove from oven and set aside to cool.

While pumpkin is cooling, place pie shell on baking sheet. Line with foil and weights, then bake (350 degrees) for 25 minutes.

While pie shell is baking, process pumpkin in food processor until very creamy and no lumps remain. Measure 15 ounces and return to food processor. Add brown sugar, spices, and salt and process for 1 minute. Add evaporated milk and process until completely homogeneous. Whisk eggs and add to pumpkin mixture; process until incorporated. Use rubber spatula to scrape sides of processor bowl and whirl again to make sure mixture is homogeneous. Scrape pumpkin mixture into 4-cup measuring cup and hold at room temperature until pie shell is finished parbaking.

When pie shell is finished parbaking, remove from oven. Remove foil and weights, then pour pumpkin mixture into shell. Place pie crust shield or foil over edge. Adjust oven rack to lowest position, then return pie to oven.

Bake until filling is slightly puffed but center is not completely firm, 25-40 minutes. Remove from oven and cool to room temperature before serving.