Truffle Fettuccine with Mushrooms, Mushrooms

cooked fettuccine pasta (water, enriched fettuccine pasta [semolina, niacin, iron, thiamine mononitrate, riboflavin, folic acid, expeller pressed canola oil, extra virgin olive oil, white cheese sauce (water, milk [milk, vitamin d3, heavy cream, american white cheese [american cheese {pasteurized milk, salt, water, sodium phosphate, milkfat, salt, cream cheese [pasteurized cultured milk and cream, salt, provolone cheese [pasteurized milk, salt, monterey jack cheese [pasteurized milk, salt, canola oil, modified corn starch, butter [pasteurized cream, natural flavors {lactic acid, starter distillate, sugar, wheat flour [bleached wheat flour enriched {bleached wheat flour, niacin, reduced iron, thiamine mononitrate, riboflavin, folic acid, malted barley flour, parmesan cheese [pasteurized part-skim milk, cheese culture, salt, romano cheese [pasteurized cow's milk, cheese culture, salt, salt, white pepper, xanthan gum, guar gum, extractives of annatto, water, contains less than 2% of salt, bisulfate of soda, ascorbic acid, sodium benzoate, potassium sorbate, yellow onion, thyme, sea salt, parmesan cheese (parmesan cheese [pasteurized milk, cheese culture, salt, powdered cellulose, spinach, black truffle finishing butter (butter [pasteurized cream, lactic acid, black truffle base [truffle juice, salt, truffle flavor, vegetable fiber, parsley