For the Cake:
3 cups walnut halves
3/4 teaspoon ground cinnamon
1/2 cup sugar
4 large eggs, separated
2 teaspoons finely grated orange zest
1 teaspoon vanilla extract (optional)
Pinch of kosher salt
3/4 cup chopped pitted dates
For the Glaze:
2 ounces bittersweet chocolate, chopped
4 tablespoons unsalted margarine (for meat meal) or butter, cut into small pieces
1 teaspoon honey
Chopped toasted walnuts, for topping
1) Preheat the oven to 350 degrees F. Coat the bottom and sides of a 9-inch-round cake pan with cooking spray and line with parchment paper.
2) Put the walnuts, cinnamon and 1/4 cup sugar in a food processor; pulse until finely ground but not powdery. Whisk the egg yolks, orange zest and vanilla, if using, in a small bowl.
3) Beat the egg whites and salt in a large bowl with a mixer on medium-high speed until foamy. Beat in the remaining 1/4 cup sugar, 1 tablespoon at a time, until soft peaks form, about 8 minutes.
4) Fold in the yolk mixture and dates, then fold in the ground walnut mixture.
5) Scrape the batter into the prepared pan. Bake until the cake is golden and a toothpick comes out clean, 23 to 25 minutes. Let cool in the pan on a rack, then run a knife along the sides and invert the cake onto a platter.
6) Make the glaze: Put the chocolate, margarine and honey in a microwave-safe bowl, cover with plastic wrap and microwave until the margarine melts, about 2 minutes. Whisk until smooth. Cool slightly, then pour over the cake. Top with walnuts.