Preheat the Oven: Preheat your oven to 170°C (340°F). Grease a small round or loaf pan, or line it with parchment paper.
Mix Yogurt and Egg Yolks: In a large bowl, whisk together the egg yolks and yogurt until smooth. Add in the flour and stir until combined.
Whip the Egg Whites: In a separate bowl, beat the egg whites until stiff peaks form.
Combine Mixtures: Gently fold the whipped egg whites into the yogurt mixture. Be careful not to overmix — just fold until combined.
Bake: Pour the batter into the prepared pan and smooth the top. Bake for 35–40 minutes, or until the cake is golden brown and a toothpick inserted into the center comes out clean.
Cool and Serve: Let the cake cool for 10 minutes in the pan before transferring it to a wire rack. Slice and serve warm or at room temperature.