Preheat the oven to 325°F.
In a small pot, heat the whipping cream on medium heat until it just begins to comes to a simmer.
Meanwhile, in a large mixing bowl, whisk together the eggs, pumpkin purée, sugar, vanilla extract, cinnamon, ginger, nutmeg, allspice, and salt.
With one hand, slowly pour the hot cream into the egg mixture while whisking continuously and vigorously with the other hand.
Take the tart crust out of the fridge and place on a baking sheet to catch any spills while baking. Pour the pumpkin cream mixture into the tart, leaving a small space so that the filling doesn't go over the edges of the crust. You can choose to pour this into the tart while it is already in the oven to prevent any spillage when transferring the whole baking sheet to the oven.
Bake for 35-40 minutes or until the edges are set but the middle is still jiggly. Let the tart cool at room temperature until just warm to the touch. Transfer to the fridge to chill for 4 hours or overnight until completely set.
Right before serving, sprinkle the surface of the tart with granulated sugar. Use a blow torch to caramelize the sugar until it forms a hard, glassy topping. Serve immediately.