Line a cookie sheet with aluminum foil and set aside.
Heat the olive oil in a deep saucepan over medium heat. Once the oil is warm (not hot), add the garlic.
When the garlic begins to get golden around the edges, about 2 minutes, stir in all of the milk and the salt.
Bring the milk to a gentle simmer, stirring often to avoid a skin forming on the surface of the milk and to avoid scorching on the bottom.
When the milk begins to lightly simmer, gradually stir in the semolina flour. Keep stirring and folding the mixture for about 3 minutes, until it begins to pull away from the sides of the saucepan.
Add the melted butter and keep folding until all of the butter is incorporated into the semolina.
When all of the butter has been absorbed, turn off the heat.
Even out the surface of the semolina mixture with a flat, spatula and immediately add the egg yolk and the cheese, working quickly to spread the yolk over the entire surface of the semolina and then folding the yolk into the semolina. This must be done very quickly as you want to fold the mixture in on itself before the yolk has a chance to begin cooking.
Once the yolk has been incorporated, add the Parmesan and continue alternating between stirring and folding the mixture until everything is blended together in a nice, dough-like mass.
Turn mixture out onto the prepared cookie sheet and flatten the "dough" with the same spatula you used before, until it's about 3/8-inch thick (you can go to a 1/2-inch if you want a heartier gnocchi, it will just take a bit longer to cook).
Set the cookie sheet aside and allow the gnocchi 'dough' to cool at room temperature until firm enough to handle, approximately 45 minutes.
Cut the gnocchi into whatever shape or size you would like (at the restaurant we cut the gnocchi into rectangular 'fingers', but you can be creative and use a biscuit cutter or juice glass to make round gnocchi).
Traditionally, Roman gnocchi are layered in a buttered dish and baked in the oven for 17 to 18 minutes at 425 degrees F. At 13 Gypsies we sear the gnocchi in a hot pan to form a crust of 'grilled' cheese while keeping the center moist and tender. Top with your favorite sauce and enjoy!
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.
Recipe courtesy of Howard Kirk and Cari Sanchez-Potter, 13 Gypsies, Jacksonville, FL