Preheat oven to 350 F.
In a plastic bag, combine flour, salt, pepper and shake to mix. Coat chicken lightly with the seasoned flour mixture. Reserve excess seasoned flour.
In a large saucepan, brown chicken in oil, on both sides. Transfer chicken to a plate and set aside.
Using the same pan, add margarine and coarsely chopped onions. Saute until onions are translucent, about 2-3 minutes.
Stir in the reserved seasoned flour, stirring until the flour is completely incorporated. Add broth, lemon juice and thyme. Bring the mixture to a boil, stirring constantly.
Place the chicken into a Pyrex dish or casserole dish large enough to allow the pieces to lie separately. Pour the sauce over the chicken, cover and bake at 350 degrees for about 20-30 min, or until the chicken is tender and opaque.
Serve with lemon wedges and a sprinkling of parsley, if desired.