Preheat your oven to 350°F (175°C). Grease a 9x13 inch baking dish.
In a large mixing bowl, whisk together the semolina, all-purpose flour, and baking powder. Set aside.
In another bowl, beat the eggs and sugar together until light and fluffy. Add the yogurt, vegetable oil, vanilla extract, lemon zest, and a pinch of salt. Mix well.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix.
Pour the batter into the prepared baking dish and spread it evenly.
Bake in the preheated oven for about 30-35 minutes, or until a toothpick inserted into the center comes out clean and the top is golden brown.
While the cake is baking, combine the water, sugar, lemon juice, and cinnamon stick (if using) in a saucepan. Bring to a boil over medium-high heat, stirring until the sugar is dissolved.
Reduce the heat and let the syrup simmer for about 10 minutes. Remove from heat and let it cool slightly.
When the cake is done baking, remove it from the oven and let it cool for a few minutes.
While the cake is still warm, cut it into diamond or square shapes. Slowly pour the warm syrup over the cake, allowing it to soak in. Let the cake absorb the syrup and cool completely.
Once the revani has cooled and absorbed all the syrup, serve it garnished with a sprinkle of ground pistachios or shredded coconut, if desired.
Enjoy your meal!