Press cooked and peeled potatoes through a potato ricer or food mill (with fine screen) into a large mixing bowl. Add flour and egg yolks and mix by hand until mixture comes together in a pliable dough. Be careful not to overwork dough, as overworking the dough will make the gnocchi dense and sticky. Add more flour if necessary. Divide dough into quarters. Gently roll out the dough on a well-floured surface into a 3/4-inch diameter snake. Cut the dough snake into 1/2-inch to 1 inch pieces. Roll over a gnocchi board, or back of a floured fork to create the signature ribbed gnocchi shape. Alternatively, simply press an indention into each gnocchi pillow. Drop the gnocchi into well-salted boiling water to cook. The gnocchi is cooked once it rises to the surface.
In a large sauté pan, melt butter over medium heat. Once butter begins to lightly brown, add cooked gnocchi. Sauté in browned butter for 3-4 minutes. Add asparagus and crumbled bacon, and cook 2-3 minutes until asparagus is tender crisp. Add sage, salt and pepper to taste. Serve with grated parmesan cheese.