Preheat the oven to 375°F / 190°C and grease an 11in / 28cm round pan.
For the syrup, simmer 1 cup of sugar, ¾ cup of water, and 1 slice of lemon for 5-7 minutes, until slightly thickened but still clear. Stir in 1 tablespoon of rose water and let it cool.
Chop 225g of thawed kataifi (shredded phyllo dough) in a food processor. Transfer it to a bowl and work in ½ cup of melted unsalted butter with your hands until evenly coated.
In another bowl, mix ½ cup of whole-milk ricotta, 2 cups of shredded mozzarella, and ¼ cup of sugar.
Press the kataifi into the pan in an even layer and spread the cheese over it, leaving the edges bare. Bake for 20-25 minutes, until the cheese is lightly golden and the edges are brown.
Turn the knafeh out onto a platter and pour the syrup over it while it is hot. Cut and serve warm.
