• Put the pumpkin puree in a large heatproof bowl and set aside. In a medium heatproof bowl, whisk the yolks just to break them up, then whisk in the cinnamon, ginger, and half of the brown sugar. Set aside. In a heavy nonreactive saucepan, stir together the cream, milk, salt and the remaining sugar and put the pan over medium-high heat. when the mixture approaches a bare simmer, reduce the heat to medium.
• Carefully scoop out about 1/2 cup of the hot cream mixture and, whisking the eggs constantly, add the cream to the bowl with the egg yolks. Repeat, adding another 1/2 cup of the hot cream to the bowl with the yolks. Using a heatproof rubber spatula, stir the cream in the saucepan as you slowly pour the egg-and-cream mixture from the bowl into the pan.
• Cook the mixture carefully over medium heat, stirring constantly, until it is thickened, coats the back of a spatula, and holds a clear path when you run your finger across the spatula, 2 to 3 minutes longer. Strain the base through a fine-mesh strainer into the container with the pumpkin puree in it. Gently stir to combine. Set the container into an ice-water bath, wash your spatula, and use it to stir the base occasionally until it is cool. Remove the container from the ice-water bath, cover with plastic wrap and refrigerate the base for at least 2 hours or overnight.

Freeze the ice cream:

• Whisk the vanilla into the chilled base. Freeze in your ice cream maker according to the manufacturer’s instructions. While ice cream is churning but the container you’ll use to store the ice cream into the freezer. Enjoy right away or, for a firmer ice cream, transfer to the chilled container and freeze for at least 4 hours.