2cupsfine almond flouralso called almond meal (225 grams)
Zest from 1 small navel orangeabout 1 teaspoon
Zest from 1 lemonabout ½ teaspoon
1teaspoonpure vanilla extract
Powdered sugar for dusting
Preheat your oven to 350 F. Generously butter a 10-inch springform pan.
Place the egg whites in a stand mixer with the whisk attachment. Beat to stiff peaks (when you pull the whisk out of the egg whites, it will form a peak that holds its shape). Remove the egg whites to a large mixing bowl and set aside.
Place the egg yolks and sugar in the mixer and beat them with the whisk attachment until thick and pale yellow, about 6 minutes. Beat in the orange zest, lemon zest, vanilla and cinnamon, then mix in the almond flour until just combined.
Add about ⅓ of the egg whites to the egg yolk mixture and fold in gently, using a spatula. The egg yolk mixture will be quite thick, and it is important to lighten it with a little of the egg whites before adding the rest. Fold in another ⅓ of the egg whites, then the remaining amount.
Pour the batter into the prepared pan, place on a baking sheet and place in your preheated oven. Bake for 40-45 minutes, until the sides have pulled away from the pan and the cake is set in the middle.
Let the cake cool completely, then dust with powdered sugar using a fine mesh sieve.