The technique illustrated below is used when making Gnocchi alla Romana.
Add the semolina in a steady stream to the heated milk, while whisking, and cook over low heat, stirring slowly until the semolina pulls away from the sides as a mass and a skin forms on the bottom of the pot. Remove from the heat and stir in the remaining ingredients.
Pour the hot mixture onto a marble surface or buttered, parchment-lined half sheet pan or hotel pan and spread with an offset spatula to 1½ to 2 centimeters (½ to 1 inch) thick. Flatten and level the mixture by pressing it with another pan. Let cool. Cut the cooled dough into rounds or squares. Shingle the gnocchi, overlapping slightly, on a buttered sheet pan, dot with butter, sprinkle with cheese, and bake until golden brown.