Preheat the oven to 425 degrees F.
Butter 1 cookie sheet with 3/4-inch sides and a baking dish.
In a 3 to 4-quart saucepan, heat to scald the milk, salt, and 6 tablespoons butter. Pour in the semolina in a thin stream, whisking vigorously, and cook for about 1 minute, switching to a wooden spoon as it thickens. Remove from the heat and stir in 1/2 cup grated cheese and 4 egg yolks. Mix well to combine. Pour the semolina onto the buttered cookie sheet and, using a spatula, spread to a thickness of 1/2-inch. Allow to cool.
Using a pastry cutter or water glass, cut 3-inch quarter moons out of semolina. Arrange the moons so that they are leaning up against one another (overlapping) in a buttered baking dish and sprinkle with remaining grated cheese. Place in oven and cook 15 to 20 minutes, or until top is deep golden brown. Remove and serve immediately.
Recipe courtesy of Mario Batali