Preheat the oven to 400°F (200°C). Line a rimmed baking sheet with parchment paper, a Silpat, or foil and set aside.
In a small bowl, whisk together the melted butter, honey, harissa, and lemon juice until smooth.
Pat the chicken thighs dry and season both sides with kosher salt to taste.
Arrange the thighs skin-side up on the prepared baking sheet. Baste the top and bottom of each thigh with about half of the harissa mixture.
Roast in the preheated oven for about 30 minutes, basting the thighs with the remaining harissa mixture once or twice during cooking.
Check for doneness with a meat thermometer; the internal temperature should reach 165°F (74°C). Tent with foil if the skin is browning too quickly.