Slice lemon in half and squeeze juice into large ziptop bag or bowl.
Add spices and 1/4 cup olive oil to the lemon juice, then add chicken thighs and onion slices.
Marinate for at least an hour or up to overnight.
When ready to cook, preheat oven to 400 degrees and pour entire contents of bag into 9x13 baking pan.
Bake for about 30 minutes or until internal temperature reaches at least 165 degrees.
Once the chicken is done, heat the remaining 1/4 cup olive oil in a large skillet over medium-high heat.
Remove pan from oven and put chicken on a cutting sheet. Using a fork and sharp knife (the chicken is hot!), cut the chicken into slices/smaller pieces.
Once the oil in the pan is hot, place the chicken slices and onion in the oil, spreading out so it is all in a single layer. Cook for 3-4 minutes, then flip it all over cook for another 3-4 minutes until chicken is crispy on both sides.
Serve with pita bread and yogurt sauce (see below).
Remove to bowl and toss with parsley.
For the sauce, stir all ingredients together in a small bowl, adding more seasoning to taste if you want.