Ingredients
3/4 cup safflower oil, plus more for pan
1 cup matzo meal
1 cup walnuts, toasted and finely ground
3/4 cup sugar
1 teaspoon ground cinnamon
1/2 teaspoon coarse salt
Grated zest of 1 large orange, plus 1/4 cup fresh juice
3 large eggs, separated, plus 3 large egg whites
3 ounces semisweet chocolate, coarsely chopped (1/2 cup)
1 ounce semisweet chocolate, melted
5 very thin orange rounds
1/3 cup walnuts, toasted and coarsely chopped
Preparation
Cake: Preheat oven to 350 degrees. Brush bottom and sides of an 8-inch square cake pan with oil. Line bottom with parchment, leaving a 2-inch overhang on 2 sides. Brush parchment with oil.
In a large bowl, whisk together matzo meal, ground walnuts, sugar, cinnamon, salt, and zest. Stir in oil, egg yolks, and orange juice.
In a mixing bowl, beat egg whites on low speed until foamy, 1 minute. Increase speed to high; beat just until stiff (but not dry) peaks form, 1 to 2 minutes more. Stir one-third of whites into batter, then fold in chopped chocolate. Gently fold in remaining whites (do not overmix). Transfer batter to prepared pan.
Bake until cake is golden on top and springs back when lightly pressed, 25 to 30 minutes. Let cool in pan 10 minutes. Remove cake using parchment and transfer to a wire rack; let cool completely.
Serving: Place cake on a platter. Drizzle with melted chocolate; top with orange rounds and walnuts.
