In a bowl, mix the semolina, flour, and baking powder. In a separate bowl, add the egg yolks and beat them with the sugar. Add the vanilla and beat with a mixer until the mixture is light and fluffy.

Add the yogurt, vegetable oil, and lemon zest, and mix well. Stop the mixer, add the flour mixture, and gently fold in with a spatula until combined. In another bowl, beat the egg whites until stiff peaks form. Gently fold the egg whites into the batter with a spatula using circular motions.

Grease a medium baking dish (such as a 9x13-inch Pyrex) and sprinkle with semolina. Pour in the batter and bake at 340°F (170°C) for about 1 hour.

While the cake is baking, prepare the syrup by boiling the sugar and water for 5 minutes, then let it cool. When the cake is ready, pour the cooled syrup over the hot cake. Let it cool, cut into pieces, sprinkle with shredded coconut if desired, and serve! Enjoy!