Preheat oven to 375°F (190°C).
Pat the chicken dry with paper towels.
Rub the chicken all over with olive oil or butter.
Season generously with salt, pepper, paprika, and herbs.
Stuff the cavity with lemon halves and garlic.
Place onion (and optional vegetables) in the bottom of the Dutch oven.
Set the chicken breast-side up on top of the veggies.
Cover and roast for 60 minutes.
Remove the lid and roast another 20–30 minutes until the skin is golden and internal temperature reaches 165°F.
Let rest 10 minutes before carving and serving.