PREP ~ Clean and slice mushrooms, set aside in bowl. Dice onion add to mushrooms in the same bowl. Mince garlic, keep separate. Pour flour in bowl or plastic bag and set aside. Cut chicken into bite size pieces. Approx 1 inch cubes. Put chicken pieces into flour and coat on all sides. Transfer chicken to another surface being sure to shake off any excess flour.
Bring water to boil in a large sauce pan for pasta. In a large skillet, heat 2 Tbl of oil on high heat. Once oil has become hot, reduce to medium-heat and put in the chicken. Cook on medium-heat for 2-3 minutes. Add pasta to boiling water.
Add the other 2 Tbl of oil and the mushrooms and onions. Cook on medium-heat until mushrooms are partially wilted. Onions will be translucent. Chicken should be nearly browned on all sides. Add garlic and cook for another 2 minutes.
Add dijon mustard, evenly coat chicken and mushrooms.
Once the mustard is evenly distributed, slowly start adding the cream, stirring in one cup at a time. You may need to turn the heat on high if cream is cold. The mixture should take between 3-4 cups of cream. You are looking for a thick sauce. Let it come to a boil, then take it off the heat.
Quickly chop the basil and add it to the chicken, slightly stirring. Your pasta should be done by this time. Drain, add to chicken and serve with bread and your favorite veggie.