In many regions, wintertime brings a relative dearth of wild foods, but not on the north coast. In fact, winter is a great time to find one of my favorite native nuts, the often overlooked, incredibly tasty black walnut (Juglans nigra). Unlike domestic English walnuts sold by most grocers, black walnuts are rarely sold commercially. This productive tree is one of the most abundant species in western California's riparian corridors and a great one for beginner foragers to pursue as it is easy to identify, not threatened by overharvesting and has a long window for gathering.
The black walnut is slightly bitter and ideal for use in sweets, its aroma coming through where that of English walnuts gets lost. Some pulverize the nuts and use them in truffles or sprinkled over baklava. I love them in homemade ice cream.
You won't find a black walnut tree in the heart of a redwood forest or the dunes near the North Jetty. However, search the lowlands of one of our rivers or streams (just up the bank from the high water mark) and you are bound to find these trees growing among alder, willow and California bay. The fruit of the black walnut tree is mature when the outer husk turns black and loosens from the nut inside, as early as the beginning of November. By mid December, most of the nuts will have fallen to the forest floor, but unlike most tree nuts, remain undamaged by insects for the next few months. Even in January or February you can find last season's nut on some trees — likely still good.
But there are a few catches. First, a black walnut on the ground often has worms between the outer husk and actual nut. Though not appetizing, they do not compromise the nut inside its almost impenetrable shell. This shell is why squirrels will leave them until every weak-shelled English walnut is gone. It's also why people say they aren't worth it. I won't lie: they are a bit of work, but there is a solution. It's called a hammer. Or a rock if you're in the field surrounded by humanity's earliest tools. After cracking the shell in several locations (not smashing it to smithereens) pry it apart and remove the meat. You will end up with four or five pieces, but if you're grinding them anyway, this is no cause for tears. Finally, don't be lazy separating out shell fragments from the similarly colored nutmeat. Nobody wants a chipped tooth.
And remember: Never gather the entire crop of any wild food, as other humans and animals would surely like to share; never trespass and always obtain required permits for harvesting on public lands, keep secret spots a secret (especially if a fellow forager shared it with you); and steer clear of potentially polluted areas such as roadsides and yards that are sprayed with herbicides.
Black Walnut Ice Cream with Pomegranate Caramel
If you cannot find pomegranates in season, the juice and a little zest of a small orange is a delicious alternative.
Ingredients and method:
1 cup half and half
1 ¹/³ cup sugar, divided
2 large eggs, separated
1 pinch salt
¾ teaspoon pure vanilla extract
Meat from 12 black walnuts
Juice of one pomegranate
For the ice cream
Place the shell-free walnut meat in a small bowl with just enough hot water to cover and set them aside to soak. In a separate bowl, using a wire whisk, beat two large egg yolks with 1/3 cup of sugar and a pinch of salt. Whisk for about one minute until it is light and smooth. Heat the half and half cream over low heat just until it begins to foam at the surface. This should take 2-3 minutes. Whisk the half and half into the egg mixture a little at a time — not all at once — to prevent the egg from cooking. Carefully heat this "custard" over a double boiler or in a saucepan over low heat, stirring continually. Once the custard thickens (about 5 mutes), remove it from heat, stir in the vanilla extract and let it cool.
Puree the walnut and water mixture into a paste and stir it into the custard. Once the mixture is cool, place it into your ice cream maker and try to be patient while it transforms. If you do not have an ice cream maker, put the cooled custard into a shallow Pyrex dish and place it in the freezer. After an hour, remove the dish and scrape the sides with a rubber spatula or wooden spoon. Return the dish to the freezer and remove it again to stir the contents every 20 minutes until you have smooth, beautiful ice cream. (Keep up with the stirring or your ice cream will not turn out nearly as light and fluffy.)
For the caramel sauce
Place a metal spoon in the freezer. Next, quarter a pomegranate and place it into the bottom of a deep pot in the sink (hopefully also deep) and crush the pieces with a potato masher. (A little juice is bound to spray out of the pot here, so don't wear white.) Run the pulp through a tight sieve, wire strainer or cheesecloth over a bowl, separating all skin and seeds from the purple juice.
Pour this juice into a saucepan and add 1 cup of sugar. Heat it on low, stirring constantly for approximately 2-3 minutes, until all of the sugar has dissolved and the sauce begins to thicken. Keep in mind it will be significantly thicker once cooled. Test the sauce by placing a few drops on the back of the chilled metal spoon from your freezer. The caramel should slowly creep down the spoon and stretch out if touched with a fingertip. Allow the caramel to cool to room temperature and serve over your ice cream. Be patient — hot caramel will rapidly melt an otherwise delicious dessert.