Season each chicken thigh with 1/2 to 3/4 teaspoon salt (depending on its size; a large thigh will weigh about 10 ounces and a small one about 6 ounces) and 1⁄4 teaspoon pepper.

Heat a black steel pan over high heat until very hot. Add 1 tablespoon of the oil and heat until the surface is rippling but not smoking. 

Working in batches to avoid crowding the pan, add 4 chicken thighs, skin side down, and lower the heat slightly, to medium-high. Weight down the thighs with a heavy plate to create an even sear across the entire surface and cook for 5 to 6 minutes, until evenly golden but not too dark in any spots. 

Check after the first 1 to 2 minutes to ensure no black spots are forming and lower the heat as needed. Repeat with the remaining oil and chicken thighs, rinsing the pan and wiping it completely dry after each

Turn the chicken over and brown the second side a little bit. The chicken will not be cooked through. Move chicken to a plate.

Repeat with the remaining oil and chicken thighs, rinsing the pan and wiping it completely dry after each set of four thighs. Move chicken to plate

Add the olive oil to the pan if needed.

Deglaze pan if necessary with a drizzle of sherry. 

Add the garlic and cook until golden. Add the onion. Add salt to quickly release water from onion. 

Sauté onion until brown about 20-30 minutes. Add several more tablespoons of olive oil if too dry to carmelize.

Add the sherry and lemon juice; stir to deglaze, scraping up any bits in the pan.

Stir in cumin, salt, pepper, artichoke hearts and olives and toss to combine.

Above steps can be made in advance if entertaining

Return the chicken to the pan in one layer 

 The edges of the chicken should be submerged but the skin should be exposed. It’s important not to cover the chicken skin completely or it won’t get crisp. tightly with a lid and cook over medium-low heat until the chicken is done . You want the chicken cooked through but moist and juicy,  45-60 minutes  total.

Pour the accumulated juices from the pan into a small saucepan. Add the chicken broth and boil until reduced by half, 5 to 7 minutes. Pour the sauce over the chicken and serve.