Prepare the crust: Heat oven to 350 degrees. Add the graham crackers, sugar and salt to the bowl of a food processor and pulse to form medium to fine crumbs, about 20 long pulses. (You should have about 2 cups.) Add the melted butter and pulse to combine. Tip the graham cracker mixture into a 9-inch pie plate and use a measuring cup to press firmly from the center to the edge to form an even crust. Transfer to the oven and bake until the crust sets, about 15 minutes. Remove and cool.

Prepare the filling: Increase the oven temperature to 375 degrees. Trim off the ends of the squash and discard. Quarter and core the squash. Fill a large saucepan with 2 inches of water and place a steamer basket inside. Bring to a boil over high heat and add the squash quarters. Lower the heat to medium, cover with a fitted lid and steam the squash until tender, about 15 minutes. Transfer the steamed squash to the bowl of a food processor and let it cool slightly, about 10 minutes. Blend until completely smooth. (You should have about 1 cup.)

Add the sugar, cinnamon, nutmeg, cloves, vanilla and salt to the food processor, and blend until smooth. Add the cream and eggs, and blend again until smooth and combined. Place the cooled pie crust on a baking sheet and scrape the squash mixture into the crust. Bake until the edges of the custard are set and the center is slightly wobbly when you shake the pan, about 1 hour, rotating halfway through. Remove the pie from the oven and allow it to cool at room temperature.

Prepare the topping: With a sharp and heavy knife, cut about 25 thin rings (less than ¼-inch thick) from one end of the squash. Scraping away any seeds and stringiness with a spoon, then set the rings aside.

Combine the sugar and 1 cup water in a medium saucepan and stir to dissolve the sugar. Add the squash slices and turn the heat on to medium. The water should cover the squash, so add more water if needed. Bring the mixture to a simmer and cook the squash slices until they are tender but not falling apart, 4 to 6 minutes. You should be able to easily poke a toothpick into the flesh. Gently remove the cooked squash onto a plate to drain and cool. Shingle the squash slices on the cooled pie and serve.