Heat the oven to 180°C / 350°F. Grease and flour a 26 cm / 10 in bundt pan.
In a large bowl, whisk 150 g / 5.3 oz of the sugar with the oil, yogurt, vanilla, and lemon zest until smooth and creamy.
Sift in the flour, cornstarch, and baking powder. Mix just until smooth. Do not overwork the batter.
In a clean bowl, beat the egg whites until foamy. Gradually add the remaining 50 g / 1.8 oz sugar and whip until glossy soft-stiff peaks form.
Fold the whipped egg whites into the batter in 3 additions, using slow upward motions to keep the mixture airy.
Pour the batter into the prepared pan and smooth the top. Tap the pan once gently on the counter to release any large air bubbles.
Bake for 30–35 minutes, or until the cake is golden and a skewer inserted comes out clean.
Let the cake cool in the pan for 15 minutes, then unmold and cool completely on a rack.
Dust generously with powdered sugar before serving.
Slice and serve with coffee, tea, or a spoonful of berry compote.
Dish type
Breakfast cake / Dessert