2 tablespoons olive oil
1 cup mayonnaise
1/2 cup finely chopped onion
1 tablespoon Dijon mustard
2 tablespoons garlic powder
2 tablespoons dry dry mustard
1 teaspoon Italian seasoning
1/4 teaspoon dried rosemary
Heat oil in a large skillet or saucepan over medium heat. Stir in the mayonnaise. Cook until thickened, about 5 minutes. Stir in onions and mustard. Pour over chicken and whisk to coat. Remove chicken from skillet and let cool.
Meanwhile, in a small bowl, mix garlic powder, dry mustard, Italian seasoning, rosemary and Italian seasoning. Mix together well and remove chicken from skillet. Pour sauce over chicken and toss lightly, so it coats all sides. Cover and let rest 10 minutes.
Heat olive oil in large skillet or saucepan. Saute chicken in oil until golden brown, about 5 minutes. Turn and saute the garlic powder mixture until fragrant. Stir in the dry mustard mixture and salt. Stir over low heat until everything is well coated.