Hearty Chicken Stroganoff

8 ounces wide noodles
6 tablespoons flour, divided
1 teaspoon salt
1/2 teaspoon black pepper
1 1/4 to 1  1/2 pounds chicken tenderloins
4 tablespoons butter, divided
6 medium mushrooms, cut into quarters
1 cup chopped onion
1/2 teaspoon dry mustard
2 cups chicken broth
1 cup sour cream
1 teaspoon ketchup

1. Cook the noodles, drain, cover to keep warm
2. Mix 4 T flour with the salt and pepper in a large bowl and mix well.  Add the chicken and toss to coat.
3. Heat 2 T butter in a large skillet over medium heat until melted.  Cook chicken in the butter.  Stir in mushrooms and onion.  Cook for 4 minutes.  Remove chicken and veggies with a slotted spoon. Reserve juices.
4. Add remaining flour and butter and the dry mustard to reserved pan juices and mix well.  Gradually stir in broth.  Cook for 3 minutes.  Stir in sour cream and ketchup.
5. Return chicken and vegetables to the skillet. Cook, until heated through.  do not boil