Preheat oven to 425 degrees F
Add 2-3 tbs of grapeseed oil and preheat cast iron pan at medium heat
Sear the leg quarters for 4 minutes per side
To the blender, add the 6 cloves of garlic, juice of 2 lemons, 1/3 cup oil, 1 teaspoon oregano, salt and pepper. Blend on high until smooth. Set aside.
Season the chicken lightly with salt and pepper on both sides. Preheat 2 tablespoons of oil in cast iron skillet at medium heat for a few minutes. When hot, sear the chicken for 4-5 minutes per side. After you sear the chicken on both sides, remove it from the pan onto a plate.
Turn the heat off. Add the fresh onion rings in an even layer to the bottom of skillet. Add chicken back in, skin side up.
Pour garlic/lemon mix over the top of chicken. Add some lemon slices to the skillet on or around the chicken. Add some parsley and place in preheated oven uncovered for 20 minutes.
After 20 minutes, take out the chicken and baste with chile ancho salsa. Place back in the oven for 20 minutes. Again take out and baste and then back in the oven for 10-15 minutes.
Remove chicken from oven and let it rest for 15 minutes before serving . If you like you can lightly brush with more chile ancho salsa right before serving.