Heat water in a large pasta pot. Add salt. Slice the mushrooms, and mince the shallot. Put a saute pan on the heat and add the butter and olive oil. When the butter has melted, add the shallot, and saute, stirring occaisonally until the shallot is translucent. Add the mushroom slices, brown on both sides then add the sherry, scraping up all the good stuff on the bottom of the pan. Reduce the heat and let the mushrooms cook completely, stirring occassionally. When the water boils, add the pasta and cook until al dente, about 8 minutes. Open the can of Chicken a la King. Drain the pasta, and return it to the pot. Important:: DO NOT RINSE THE PASTA. Add the can of Chicken a la King, cheese and mushrooms. Toss and serve.