Start by pre-heating the oven to 400F
Thinly slice the onions into half moons (I do this using a mandolin) and place them on a parchment lined sheet pan.
In a bowl, mix together the olive oil and the spices until they're well combined, reserving 1 tablespoon of the sumac.
Place about one tablespoon of the spice paste over the onions and toss them together to ensure they are all coated. Spread them into one even layer.
Place the chicken thighs over the onions and add the rest of the spice paste. Use your hands to evenly coat the chicken with the spice paste.
Bake in the oven for roughly 30-35 minutes, until juice run clear and chicken is white on the inside (you can test a piece). Broil for 5 minutes to achieve a bit of colour on the chicken. Sprinkle the remaining sumac on top of the chicken and onions.
Garnish with parsley, toasted pine nuts and lemon wedges. Serve with bread or a side of rice and enjoy!
