Black Walnut–Dark Chocolate Tart

So what’s a black walnut? Maybe you’ve tried them and you already know, but for those of you who don’t, black walnuts grow wild in many parts of the U.S. You might have seen them on the ground in early fall, looking like little green tennis balls with sticky black sap oozing out of any breaks in their skin. The green outer shell needs to be removed to reveal the craggy inner shell, then the inner shell needs to be cleaned of all of the sap, and only then can the inner shells be cracked open to reveal the nut meats. At that point, the nut meats need to be carefully picked out of the shell bit by bit.

I lived in Miami until I was five, and I remember every fall getting a large box of black walnuts in their inner shells, sent by my grandparents, who collected them on the campground where they lived in Pennsylvania. My grandfather would drive his car over the walnuts to crack open the outer shell, and he and my grandmother would clean the walnuts and send them to us in Florida, where, in the southern part anyway, black walnuts do not grow. My mother and I would take the box out to the back patio and smash the walnut shells open with a sledgehammer. In my memory I was an active participant in the walnut-smashing, but it seems unlikely that I was really running around wielding a sledgehammer as a four-year-old, so perhaps she smashed and I offered moral support. In any case, after the smashing (in the aftersmash?), picking out the nut meats always took several hours, and our final yield was not enormous. How delicious, though. The taste is less bitter than that of English walnuts, and the texture more creamy, with a flavor that I can only describe as very wild, and concentrated.

Now you can find shelled black walnuts any old place on the internet (a good thing—I’m not sure how our neighbors would take to having people smashing open walnut shells on the sidewalk in Brooklyn, though it does seem like a very Brooklyn thing to do). Even if you buy them already shelled, make sure to pick through the walnuts for any stray shell bits that could at best cause an unpleasant crunch and at worst break a tooth!

I was reading through Edna Lewis’s In Pursuit of Flavor other day, and in her recipe for Black Walnut Pound Cake, she writes of her memories of her aunt driving over the walnuts to break apart the outer shells. I’m not sure that there’s a better way to break the shells than driving over them, actually, but reading that made me smile and feel connected to one of my favorite chefs, though my experience came more than 50 years later.

Black Walnut–Dark Chocolate Tart

for the crust

8 oz. cold, unsalted butter (1 stick), cubed
1/2 cup whole wheat flour
1/2 cup unbleached all-purpose flour
1/2 tsp coarse salt
2-3 Tbsp iced water
9-10 inch tart pan

for the filling

3.5 oz. high-quality dark chocolate
6 Tbsp + 1 Tbsp unsalted butter, at room temperature
1 1/2 cups black walnuts, lightly toasted*
2/3 cup light brown sugar
1 egg
2 Tbsp heavy cream, plus more for the whipped cream
1 tsp vanilla extract
1/4 tsp salt

Make the crust. In a medium bowl, mix the flours and salt. Dump in the butter and using your hands, work and squeeze it into the flour until it’s crumbly and sandy. Add iced water bit by bit and knead until the crumbs come together into dough, then stop. Wrap dough ball in plastic wrap and refrigerate for 1 hour.
Roll out the dough until it’s big enough to go into the tart shell with a slight overhang. Press dough into the tart shell, prick all over with a fork. Put shell into the freezer for 15 minutes. Meanwhile, preheat 0ven to 375º. Line tart tightly with foil, wrap around edges. Bake 20 minutes, then remove foil, reduce heat to 350º, and bake 15 minutes more, or until golden brown. Remove from oven and set aside to cool. Increase oven heat to 400º.
Make the filling. Simmer some water in a small pot. Put chocolate and one tablespoon butter in a metal bowl; place bowl on top of the pot of simmering water. Stir until everything is melted and combined. Pour melted chocolate into the tart shell, spreading around the bottom and up the edges.
More filling. In a medium bowl, mix remaining butter and brown sugar until creamy. Add egg, heavy cream, vanilla, and salt; stir until combined. Add walnuts and stir. Pour into crust, even it out, smooth the top. Bake at 400º for 15 minutes. Let cool before serving with lots of whipped cream.

*Note: If you can’t find black walnuts, you can use chopped English Walnuts. The taste will be different but still good.