In a large mixing bowl, combine olive oil, harissa powder, lemon juice, smoked paprika, cumin, and cayenne pepper. Stir until the mixture forms a thick paste.

Rub the harissa paste generously over the chicken thighs or place them in a bag with the marinade. Let marinate for at least 1 hour in the fridge.

Preheat your oven to 425°F (220°C) to achieve a crispy exterior.

Line a baking tray with foil or parchment paper and arrange the marinated chicken in a single layer.

Bake for 18-20 minutes, until the internal temperature reaches 165°F (75°C) and edges are crispy.

Let the chicken rest for about 5 minutes before serving.