Preheat the oven to 350°F (175°C). Line a round cake pan with parchment paper, making sure it covers the bottom and sides.
In a large mixing bowl, whisk together the egg yolks, natural yogurt, sugar, corn starch, and baking powder until smooth and well combined. Set aside.
In a separate clean bowl, whisk the egg whites with a pinch of salt. Beat until soft peaks form. Gradually add in the remaining sugar and continue beating until stiff peaks form.
Carefully fold the beaten egg whites into the egg yolk mixture. Use a gentle folding motion to avoid deflating the egg whites.
Pour the batter into the prepared cake pan and smooth out the top. Bake for 30-35 minutes or until the cake is set and lightly golden on top.
Let the cake cool in the pan for a few minutes, then transfer to a wire rack to cool completely. Once cooled, slice and serve.