1 teaspoon olive oil
1 teaspoon garlic powder
1 pound boneless chicken breast halves
1 pound celery quarters
1 cup sliced fresh mushrooms
1/2 cup diced onion
1 cup chopped fresh mushrooms
1 teaspoon dried oregano
1 teaspoon dried basil
2 1/3 cups water
1 teaspoon salt
1 teaspoon dried basil
1/2 teaspoon pepper
7 ounces spaghetti sauce
Heat olive oil in a large saucepan over medium heat. Cook chicken until no longer pink; remove and set aside.
Preheat oven to 350 degrees F (175 degrees C).
In a large bowl, mix together garlic powder, celery and mushrooms. Stir in onion, mushrooms and celery quarters. Stir in water and salt, and combine with chicken.
Combine spaghetti sauce with chicken, mushrooms and celery quarters and sprinkle evenly over chicken.
Bake uncovered 5 to 10 minutes longer for a firmer, rounder finish. Remove chicken from oven. Brush with egg and sauce mixture, and season with salt, basil and pepper.
Remove chicken from oven and brush with sauce mixture. Bake 30 minutes longer, uncovered, for 15 minutes.