Preheat oven to 375 degrees. spray a rimmed half sheet pan with non-stick spray.
Add the butter to a small mixing bowl with the garlic, onion powder, parsley, and salt. Stir well and set aside.
Trim the ends of the green beans and place in a single layer on the sheet pan.
Cut slits in the chicken breasts (optional, but encouraged) and lay on top of the green beans.
Season chicken with salt + pepper to taste and brush the garlic butter evenly over everything.
Bake for 25 minutes or until the chicken is cooked through.
