Start by pouring the milk into a saucepan and heating it gently over medium heat. Add the lemon zest and bring it close to a simmer, but don’t let it boil. Stir occasionally to prevent sticking.
Slowly sprinkle the semolina into the warm milk while whisking continuously. This step is important to avoid lumps. Keep stirring until the mixture thickens into a smooth, creamy consistency.
Add sugar and a pinch of salt to the semolina mixture. Stir well until the sugar dissolves completely. Let it cook for another minute or two to blend the flavors nicely.
Remove the saucepan from heat and stir in the butter and vanilla extract. The butter will melt into the mixture, making it rich and smooth. Allow it to cool slightly before adding eggs.
In a separate bowl, lightly beat the eggs. Gradually add them to the semolina mixture while stirring quickly to avoid scrambling. This step gives the cake its soft structure.
Preheat your oven to 180°C (350°F). Grease a baking dish lightly with butter. Pour the prepared batter into the dish and smooth the top evenly.
Place the dish in the oven and bake for about 35–40 minutes. The top should turn golden and slightly firm. Let the cake cool before slicing to allow it to set properly.