Preheat your oven to 425°F (220°C).

Place the chicken breast-side down on a cutting board. Using kitchen shears, cut along both sides of the backbone to remove it, then flip the chicken over and press down firmly on the breastbone to flatten it completely.

In a small bowl, mix the softened butter, harissa paste, minced garlic, cumin, paprika, lemon zest, salt, and pepper until well combined.

Gently loosen the skin from the chicken breast and thighs using your fingers. Spread half of the butter mixture underneath the skin directly onto the meat.

Rub the remaining butter mixture all over the top of the skin.

Place the chicken on a baking sheet or in a roasting pan. Drizzle with olive oil and pour the lemon juice over the bird.

Roast for 45 to 55 minutes, or until the skin is deeply browned and crispy, and the internal temperature reaches 165°F (74°C) at the thickest part of the thigh.

Remove from the oven and let the chicken rest for 10 minutes before carving to allow the juices to redistribute.