If you crack your own black walnuts, put them in a bowl of cool water to remove any small pieces of shell. Remove the walnuts and dry.
Whisk the cream, cornstarch or eggs, vanilla extract and salt.
In a small 1 quart sauce pan over high heat, bring the maple syrup to a simmer.
Bring the maple to a rolling boil and cook for 4-5 minutes, or until the bubbles try to creep up the sides of the pan. Add the corn syrup and cook on high for two minutes more.
If using eggs, do not boil the mixture, but cook it gently, whisking constantly until just thickened.
Whisk the cream again to ensure the cornstarch is dissolved, then pour into the pan with the hot maple.
Add the walnuts. Heat on medium-high heat, whisking constantly until the mixture starts to thicken.
Turn off the heat, pour the ice cream base into a metal bowl, whisking to dissolve and lumps and scraping every bit of ice cream base into the bowl with a spatula.
Cover with cling film and cool, then chill overnight.
Process the ice cream base according to the manufacturers directions. It should take about 30 minutes to churn, and should look like soft serve ice cream when it’s done.
Transfer the ice cream to a container with a tight fitting lid and freeze. It will take about 12 hours to set as salt, cream and corn syrup resist freezing.
Video
Notes
Variations
Black Walnut Maple Ice Cream This version has nuts at the front with maple in the background. Follow the recipe for Maple Black Walnut Ice Cream using: 2 cups half and half, 1 cup cream, ½ cup sugar, ¼ cup maple, 2 tablespoon cornstarch, ½ teaspoon salt. Classic Black Walnut Ice CreamThe classic recipe has the strongest black walnut flavor. Use 3 cups half and half, ¾ cup sugar, 2 tablespoon cornstarch, ½ teaspoon salt. This is demonstrated in the video.