In a large pan we heat the olive oil over medium heat. We add the onions, lower the heat a tad, and cook for about 15 minutes. We stir the onions occasionally as they cook, we want them tender and golden. Next we add the sliced mushrooms, raise the heat to medium, and cook for 5 minutes. Then we add the garlic, salt and pepper, and dried sage and keep on low heat while we cook the chicken and strain the porcini.
We strain the porcini over a bowl into a paper-towel lined strainer. We rinse the porcini, chop coarsely, and add them to the mushroom pan. We pour the strained porcini liquid one more time through a clean paper-towel lined strainer. We reserve this liquid in a measuring cup.
After the chicken is sauteed and removed from a second pan, we add the butter to the drippings. When it is melted, we add the flour and stir for about a minute. Off the heat, we add the wine, stirring until smooth and scraping up the browned bits on the bottom of the pan. Then we stir in the porcini liquid, and pour the wine-porcini sauce into the mushroom pan. We boil the mushroom sauce for a few minutes. Finally, we add the pasta, the fresh parsley and basil, freshly ground black pepper, and some Locatelli cheese.
We serve the pasta with the sauteed chicken.