Add foie gras to a comfort food favorite.
Preheat the oven to 250 degrees.
Place foie gras in a small baking dish, cover with foil, and render in the oven for 10 minutes (some of the fat will have melted out so it resembles softened butter).
Meanwhile, bring water to a simmer in the bottom half of a double-boiler. In the top bowl of the double-boiler, whisk together the sugar and egg yolks off the heat. Whisk in the port and place the bowl on top of the simmering water. Whisk continually until the mixture thickens and forms a long, thick stream, like a ribbon, when you lift the whisk, 5 to 6 minutes. Transfer to a food processor.
With the food processor running, slowly add the foie gras (both the solids and rendered fat). Add the butter 1 piece at a time. Continue to run the food processor until all the butter is incorporated before slowly pouring in the cream. Watch very carefully and as soon as it begins to look thick, stop the machine. (Due to the high fat content, it can turn to butter if it is churned too much.) Pour the mixture through a fine-mesh strainer into a bowl. Immediately pour the mixture into an ice cream machine and freeze according to the manufacturer’s instructions. Store in an airtight container in the freezer for up to 2 weeks until ready to use.