INGREDIENTS2 1/2 cups,
fine semolina flour
1 1/2 ounces,
Adjust oven rack to middle position and heat oven to 400 degrees. Heat milk, salt, and nutmeg in medium saucepan over medium-low heat until bubbles form around edges of saucepan. Whisking constantly, slowly add semolina to milk mixture. Reduce heat to low and cook, stirring often with rubber spatula, until mixture forms stiff mass that pulls away from sides when stirring, 3 to 5 minutes. Remove from heat and let cool for 5 minutes.
Stir 3 tablespoons butter and egg into semolina mixture until incorporated. (Mixture will appear separated at first but will become smooth and a bit shiny.) Stir in Gruyere, rosemary, and baking powder until incorporated.
Fill small bowl with water. Moisten 1/4-cup dry measuring cup with water and scoop even portion of semolina mixture. Invert gnocchi onto tray or large plate. Repeat, moistening measuring cup between scoops to prevent sticking. Place tray of gnocchi, uncovered, in refrigerator for 30 minutes. (Gnocchi can be refrigerated, covered, for up to 24 hours.)
Rub interior of 8-inch square baking dish with remaining 1 tablespoon butter. Shingle gnocchi in pan, creating 3 rows of gnocchi each. Sprinkle gnocchi with Parmesan cheese. Bakeuntil tops of gnocchi are golden brown, 35 to 40 minutes. Let cool for 15 minutes before serving.