If you’re a seafood lover, reimagine this dish by swapping in a mild white fish like halibut, cod or snapper.
Preheat oven to 400 degrees.
In small bowl, whisk olive oil, basil, garlic, salt, pepper and oregano until combined.
Combine 2 tablespoons oil mixture and chicken in resealable plastic bag. Let stand 5–10 minutes at room temperature to marinate.
In medium skillet, heat 2 tablespoons oil mixture over medium heat. Add onions; cook 3–4 minutes or until crisp- tender. Stir in marinara sauce. Pour mixture into lightly greased 13-by-9-inch baking dish.
Arrange chicken breasts in dish, overlapping if necessary. Top with grape tomatoes and cherry tomato stems. Spoon remaining oil mixture over tomatoes.
Bake, covered, for 25 minutes or until chicken reaches 165 degrees and tomatoes start to burst.
Sprinkle with Parmesan, drizzle with balsamic glaze and garnish with fresh basil leaves before serving.