turkey breast, thawed
Shake flour in oven bag; place in 13x9x2" baking pan.
Add gravy mix and water to bag.
Squeeze bag to blend ingredients.
Sprinkle turkey breast with salt and pepper; place in bag.
Place onion in bag around turkey.
Close bag with nylon tie; cut 6 half-inch slits in top.
Insert meat thermometer through slit in bag into thickest part of turkey breast, but not touching bone.
Bake until meat thermometer registers 170 to 175, 1 1/4 to 1 3/4 hours.
Let stand in bag 15 minutes before slicing.