Preheat the oven to 180 °C / 350 °F. Place the rack in the middle of the oven. Grease a deep baking dish (30 cm X 20 cm or 12-inch X 8-inch ) with butter.
Make the crepes and soak the sultanas
Make the crepes by following this recipe. Place the sultanas or raisins into a saucepan. Add the Port or Rum and water. Place over medium heat and cook for 2 - 3 minutes, then remove from the heat and leave the mixture to cool.
combine the ingredients for the filling
Stir to combine ricotta, sour cream, lemon zest, sugar, semolina, butter, and eggs in a bowl. Add drained sultanas and stir into the mixture. Set aside for 10 minutes for the ingredients to combine. This is essential for easier crepe filling later.
fill the crepes
To assemble the crepes, add three tablespoons of the filling in the center of each crepe. Leave about an inch or 2 cm of edge. Tuck the side ends in and roll into a burrito shape. This way, the filling won't be spilling out while baking.
make the topping
Transfer the filled crepes into the prepared baking dish. Line them up closely and tightly together. Make the topping. In a bowl, stir to combine the sour cream, eggs, a pinch of salt, icing sugar, and flour to get a smooth mixture. Pour over the crepes in the dish.
bake and serve
Place the baking dish with the ricotta crepes into the preheated oven. Bake for 45 minutes at 180 °C / 350 °F. Remove from the oven, set aside for 10 minutes, dust with icing sugar, cut into eight slices, and serve.