170g1 1/2 sticks unsalted butter or margarine, at room temperature
Icing sugarfor coating the pan
500g3 cups blanched slivered almonds
1 1/4cupssugar
4large yolks
2teaspoonsgrated lemon zest
2teaspoonsgrated orange zest
1/2teaspoonsalt
1/2teaspoonground cinnamon
1teaspoonpure vanilla extract
4large egg whites
Icing Sugar
Instructions
Position the rack in the middle of the oven and heat to 170C (350F). Grease a 10-inch springform pan with butter or margarine, line the bottom with parchment paper, and grease the paper. Coat the pan with icing sugar and tap out the excess.
Grind the almonds and 1/4 cup of the sugar in a food processor until the consistency of fine cornmeal. Make sure the almonds are as finely chopped as possible. Add the butter or margarine and pulse to combine. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, or with a hand-held mixer in a big bowl, beat 3/4 cup plus 2 tablespoons of the sugar and the yolks on medium-high until very light and fluffy, about 7 minutes. Add the zest, salt, and cinnamon and mix until incorporated. Add the almond mixture and vanilla.
In an impeccably clean bowl, whisk the egg whites until foamy then slowly whisk in the remaining 2 tablespoons of sugar until the whites form soft, luscious peaks. Add about one third of the egg whites to the almond mixture and stir to lighten. Carefully fold in the remainder of the whites until no streaks show. Spoon the batter into the pan and smooth the top.
Bake until the cake is golden brown and begins to pull away from the sides of the pan, about 45 minutes. Transfer to a rack and let rest for 5 minutes before releasing the cake from the pan. Cool completely before serving. The middle will collapse a bit; that is as it should be. Sift icing sugar on top of cake before serving.