Preheat oven to 400F (200C).

Place 1/2 lemon and 1/2 garlic head into the chicken's cavity.

Place the chicken into a roasting tray.

Mix softened butter, crushed garlic, and half of the ras el hanout spice mix and smoked paprika (if using) in a bowl.

Spread the butter mixture over the chicken breast and legs.

Season the chicken generously with salt and pepper.

Prepare the chicken up to a day ahead and keep covered in the fridge if desired.

Place the remaining garlic head halves into the roasting tray around the chicken.

Roast the chicken for 1 hour.

Mix the remaining ras el hanout spice mix into the Greek yogurt and season with salt and pepper.

Remove the chicken from the oven.

Smother the chicken with the spiced yogurt mixture.

Spoon some of the roasting juices over the chicken.

Add the remaining lemon halves to the roasting tray.

Roast for an additional 15 minutes, or until the yogurt is golden and set, and the chicken juices run clear when pierced.

Lift the chicken onto a cutting board.

Cover the chicken loosely with foil and let it rest for 10 minutes before carving.

Carve the chicken and serve hot or cold.