Pour milk into a saucepan and bring to just under boiling point. Lower the heat, keeping milk hot but not even at a simmer.
Sprinkle the semolino slowly into the milk stirring continually and vigorously with a whisk to avoid lumping.
Scrape the sides and bottom of saucepan as you stir. Keep stirring until the semolina-milk mix turns thick; about 10 to 15 minutes.
Remove from heat.
Pour the semolina mix into a bowl adding 1/3 of the butter, half the Parmesan, salt and the 2 egg yolks.
Mix quickly and thoroughly making sure the egg does not set.
Use a wet spatula or scraper to spread the mix onto a lightly moistened kitchen counter or slab of marble to a thickness of about 1/2 an inch.
Let the mixture cool for a 1/2 hour or so.
Shape into small circles using a moistened cookie cutter or small glass, a liqueur glass works fine.
Preheat oven to 425° F.
Butter the bottom of an ovenproof dish and cover with a layer of gnocchi. Overlap the gnocchi a bit.
Dot with butter and sprinkle with Parmesan.
Continue layering till all the mix is used up.
Place dish in oven on the top rack and bake until a light golden crust forms (15 minutes). If the surface of the dish has not formed a light brown crust turn the heat up and bake for a few minutes more, or place under the broiler for a minute or two, careful not to burn the surface.
Serve the gnocchi from the baking dish with lots of grated Parmesan cheese on the side. Can be prepared ahead of time and refrigerated for up to two days. Seal well with tin foil. Bring it to room temperature when you are ready to bake it.