Roast Chicken with Croutons and Onions

1 (4 pound) whole chicken

1 tablespoon olive oil, or as needed

salt and ground black pepper to taste

1 large rosemary sprig, leaves stripped and finely chopped

1 large white onion, cut into 1-inch chunks

2 cups cubed French bread

1 large whole rosemary sprig

¼ lemon, juiced

Rinse chicken, pat thoroughly dry with paper towels, and allow to reach room temperature.

Preheat oven to 390 degrees F (199 degrees C).

Rub olive oil over outside of chicken and sprinkle skin and inside of cavity generously with salt. Rub black pepper and chopped rosemary onto chicken skin. Place 2 or 3 chunks of onion and French bread into cavity, along with whole rosemary sprig. Place chicken into a cast iron skillet and arrange remaining onion and bread chunks around the bird; squeeze lemon juice over the chicken, onion, and bread cubes.

Bake in the preheated oven for 30 minutes and turn chicken over so breast side is down. Bake 30 more minutes; turn chicken back over so breast side is up. Bake until chicken is browned and the juices run clear, an additional 30 minutes (90 total minutes roasting time). An instant-read meat thermometer, inserted into the thickest part of a thigh, not touching bone, should read at least 160 degrees F (70 degrees C). Let chicken rest 5 to 10 minutes before slicing chicken meat and serving with onion and bread cubes.