Boil pot of salted water for pasta; cook pasta according to directions on the box.
Heat the oil in a large skillet over medium heat.
Season the chicken thighs with salt and pepper.
Place them in the hot skillet skin- side down. Cook until the skin is crispy and golden brown, approximately 4 to 5 minutes. Flip the chicken over and continue cooking for an additional 4 to 5 minutes.
In a small bowl, whisk together chicken stock and relish until combined.
Pour the mixture into the skillet; bring to a boil. Turn the heat to low and simmer for 15 to 17 minutes or until the chicken is cooked through.
In a separate bowl, mix the butter and cornstarch together to form a paste. Stir the butter mixture into the sauce and continue cooking until thickened. Stir in the spinach.
Sprinkle the chicken with parsley and serve over the pasta. Serve immediately.
