1 1/2 cups pitted dates (1/2 pound), finely chopped
1 1/2 cups walnuts (5 ounces)[140g], toasted and cooled
3/4 cup/150g sugar, divided
2/3 cup matzo meal
1 tablespoon grated orange zest
1/2 teaspoon ground cardamom
1/4 teaspoon salt
4 large eggs, separated, at room temperature 30 minutes
Preheat oven to 350F with rack in middle. Generously grease a 9- by
2-inch round cake pan with softened butter or vegetable oil and dust
with some matzo meal, knocking out excess.
Pour hot water over dates in a large bowl and let stand 15 minutes
to soften. Pulse walnuts in a food processor until chopped, then add
1/4 cup sugar and pulse until nuts are finely ground. Add matzo meal
(2/3 cup), zest, cardamom, and salt and pulse until combined.
Beat egg whites with a pinch of salt in a bowl using an electric
mixer at medium-high speed until they just hold soft peaks. Add
remaining 1/2 cup sugar in a slow stream, beating until whites hold
stiff glossy peaks. Whisk yolks into date mixture. Fold one third of
yolk mixture into whites, then fold in remaining yolk mixture gently
but thoroughly. Fold all of nut mixture into batter.
Spoon batter into cake pan and bake until golden and springy to the
touch and cake just begins to pull away from side of pan, 35 to 40
minutes. Cool in pan on a rack 30 minutes, then invert onto rack and
cool completely. Serve with whipped cream.