In plastic bag, combine flour, salt and pepper and shake to mix.
Add chicken and shake to coat lightly.
Remove the chicken and reserve excess flour.
In large skillet, warm 1 tablespoon oil over medium heat.
Add chicken and brown on one side about 5 minutes.
Add remaining 1 tablespoon oil, turn chicken and brown about 5 minutes.
Transfer chicken to plate and set aside.
Melt margarine in skillet, add onion and cook, stirring until softened, about 2-3 minutes.
Stir in excess flour and stir.
Add broth, 2 tablespoons lemon juice, and thyme.
Bring mixture to a boil, stirring constantly.
Return chicken to skillet and cook about 5 minutes.
Remove chicken to plate.
Add 1 tablespoon lemon juice to sauce and pour sauce over chicken.