Place the egg yolks into a large bowl, set over a damp dishcloth. This will help keep the bowl stable as you whisk and pour the cream into the bowl at the same time. Slowly pour in just a little of the cream mixture, whisking constantly to temper the egg yolks. Once they are tempered, continue streaming in the remaining cream and whisking all the while. Add in the pumpkin puree and whisk together to a smooth consistency.
When ready to serve, sprinkle 1-2 teaspoons of sugar evenly over the surface of each custard (depending on the width of your ramekins), tilting the ramekins to move the sugar around.
Use a torch to brûlée each custard. Serve. See Notes
If making homemade pumpkin or squash purée, it may have a different sweetness from canned pumpkin. Feel free to taste and adjust the amount of sugar for your custard filling.
If you don't have a kitchen torch to create the sugar crust, you can place the ramekins onto a baking sheet an proceed with the sugar layer. Place the baking sheet under the broiler. The sugar will start to bubble and brown, but not necessarily as evenly as a torch can create. But the effect will be there. Cool down before serving, as the sides of the ramekins will be hot.
For an alternate dessert, for when you don't want to pull out the torch, or if you don't have one, why not whip up the remaining egg whites with creme of tartar and a bit of sugar, and create a lovely meringue to top each custard. Or make up a batch of my Forget Me Not Meringue Cookies and serve them on the side. In this case, I would serve the custards with a dollop of sweetened whipped cream.