Cut a small pumpkin into large chunks and remove the strings and seeds. Steam the pumpkin on a steaming rack in a large pot over boiling water until the pulp is soft, (usually this takes about half an hour). Let the pumpkin cool slightly and scrape the pulp from the skin. Now blend the pulp until smooth and set aside.
In a double boiler set above gently boiling water heat 1 and 1/4 cups of heavy cream.
In a large bowl whisk 6 egg yolks, 2/3 cup coconut sugar, 1/3 cup maple syrup, 1 tsp. ground ginger, 1/2 tsp. ground cinnamon, 1/4 tsp. freshly grated nutmeg and a 1/4 teaspoon allspice.
Gradually pour 1/4 cup of the hot cream into the egg mixture, whisking constantly, then whisk the egg/cream mixture back into the remaining hot cream atop the double boiler.
Double boil for a few minutes whisking constantly with a small wire whisk while regularly scraping the sides of the pot with a heat-resistant spatula. Whisking is to add air to the mixture and the occasional lets call it, spatulation is to help remove the thickening mixture from the surface of the pot where the heat is highest.
Just keep on whisking and spatulating, aerating the mixture until the egg-cream melange is thick enough to coat the back of a spoon or spatula. Though this can sometimes feel like an eternity, in fact, it only takes about ten minutes or so. Experience also instructs that the best way to avoid custard frustration is through constant tasting. Adding a pinch of ground cloves here, or perhaps a hint of five-spice powder there can also help to pass the time.
Finally, pour the custard through a sieve set over a clean bowl, adding 2/3 cup of pureed cooked pumpkin, (organic canned pumpkin is fine) a generous teaspoon (or two) of vanilla extract (of course a scraped vanilla pod would be preferable) and another 1/4 cup of very cold cream.
Now whisk again and refrigerate the custard for an hour or two until quite cold. At that point you an transfer the chilled custard to an ice-cream maker or thick metal bowl for freezer-whisking until you have reached the desired consistency. This makes about 1 quart.