Unbleached white spelt flour is both light and nutritious; a perfect flour for baking, especially because it contains gluten that is more crumbly than wheat, is characterized by its elasticity, and has lower absorption properties than wheat.
Preheat the oven to 325°F (160°C). Place the rack in the middle of the oven. Butter an 8-inch (20 cm) springform pan. Cut a circle of parchment paper the same size to line the bottom of the pan.
In a bowl, beat the egg whites until soft peaks form, add the sugar and salt, and beat again until stiff peaks form.
In another bowl, whisk the egg yolks, cream cheese, cornstarch, and vanilla until smooth. Add the lemon zest and juice and mix.
Sprinkle the flour and baking powder over the mixture and whisk again. Fold in one-third of the beaten egg whites. Using a spatula, fold in the rest of the egg whites, gently folding the mixture to maintain its volume.
Pour the mixture into the pan and bake for 45 minutes. Let cool completely before removing from the pan. Using a sieve, sprinkle powdered sugar over the cooled cake and serve.
