Heat oven to 350℉. Season the chicken thighs with salt and pepper and let rest while you prepare the anchovy-garlic oil. Mince one garlic clove and set it aside for later. In a large, oven-proof skillet over medium-high heat, add the oil. When the oil is hot, add the 5 smashed garlic cloves, the anchovies, capers and chili. Let cook, stirring with a wooden spoon to break up the anchovies, until the garlic browns around the edges and the anchovies dissolve, 3-5 minutes.
Add the chicken thighs and cook until nicely browned on one side, 5 to 7 minutes. Flip the thighs, place the pan in the oven and cook another 5-10 minutes, until the chicken is cooked through.
When the chicken is done, transfer the thighs to a plate (be careful, as the pan handle will be hot). Place the skillet back on the heat and add the minced garlic and the juice of half of the lemon. Cook for about 30 seconds, scraping the browned bits from the bottom of the pan. Return the chicken to the pan and cook in the sauce for another 30 seconds.
Transfer everything to a serving platter. Squeeze the remaining lemon half over the chicken and garnish with chopped parsley. Serve
