"This is a great way of dressing up chicken in a new way! I played around with ingredients and unexpectedly came across a delicious recipe! It's tangy and savory at the same time, and goes great with any side dish."
Preheat oven to 350 degrees F (175 degrees C). Line a baking sheet with parchment paper. Grease with cooking spray.
Mix mayonnaise, Dijon mustard, rosemary, garlic powder, salt, and pepper together in a bowl.
Season chicken breasts lightly with salt and pepper. Arrange seasoned-side down on the baking sheet. Spread 1/4 of the mayonnaise mixture over each chicken breast with a spatula.
Bake in the preheated oven until center is no longer pink and top is lightly browned, about 35 minutes. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C).