1. Make an ice bath by putting some ice and a little water in a large bowl and nest a medium-sized metal bowl (one that will hold at least 2 quarts, 2l) inside it. Set a mesh strainer over the top. Pour the cream into the smaller bowl.
2. In a medium saucepan, warm the milk, granulated sugar, and salt. Whisk together the egg yolks in a separate bowl.
3. Whisk about half of the warm milk into the yolks, stirring constantly.
5. Scrape the warmed yolks back in to the saucepan and cook over low heat, stirring constantly and scraping the bottom with a heatproof spatula, until the mixture thickens and coats the spatula. If using an instant-read thermometer, it should read between 160º-170ºF (71º-76ºC).
6. Immediately pour the mixture through the strainer into the heavy cream, in the bowl nested in the ice bath. Stir for a few minutes until it’s cool, then puree the custard in a blender with the pumpkin puree, brown sugar, vanilla, cinnamon, ginger, pepper, and whiskey or brandy, if using. (Wipe the bottom of the bowl dry before pouring as you don’t wan to get any water into the custard mixture.) Chill thoroughly in the refrigerator, preferably overnight.
7. Freeze in your ice cream maker according to the manufacturer’s instructions.