Cut chicken into thin strips.
In a gallon size ziplock bag, combine 1 c. flour, salt, and pepper.
Add meat to bag and shake to coat.
In a large skillet, melt 3 Tbsp. butter.
Place chicken in skillet and saute until browned on all sides. Remove chicken and set aside.
Add remaining butter to skillet.
Add mushrooms, onions, garlic, and lemon juice. Saute until onions are tender.
Sprinkle with flour; cook, stirring, one minute.
Add chicken broth. Bring mixture to a boil, stirring constantly, until thickened.
Stir in mustard and sour cream.
Stir in browned chicken and heat through.
Serve over prepared Reames Frozen Egg Noodles.