Heat a cast iron/any oven safe skillet over medium high heat. To the hot pan add 2 tablespoons of butter.
Salt and pepper skin side of the chicken thighs and place skin side down on the cast iron skillet. Cook for around 5 minutes, or until they are golden brown. While the first side is cooking, make sure to salt and pepper the side facing up. Flip and cook for another 5 minutes, then remove chicken from heat and set aside. If you had really large chicken thighs like I did, you made need to cook these in two batches.
Drain some of the chicken fat, if you need to, so that you have around one tablespoon left in the pan. Add the onion and cook for about 3-4 minutes, or until the onions have started to brown. Add the garlic and cook for another 2 minutes.
Stir in tomato paste and evenly coat the onion garlic mixture. Cook for another two minutes or until the paste started to turn slightly brown.
Pour in the chicken broth. Stir to combine. Add the Harissa sauce and let simmer for approximately 5 minutes. Stir the sauce about every minute to ensure everything is incorporated.
Nestle the chicken into the Harissa cauliflower. You can place as many thighs as you want in the skillet, as long as there is a little bit of room and they are not touching.
Bake for 20-25 minutes at 425 degrees. Let cool out of the over for several minutes and garnish with lemon wedges if you desire!
