Preheat the oven to 425°F and line a large sheet pan with parchment paper. In a large bowl, toss the quartered potatoes and onion wedges with 2 tablespoons of olive oil, half the salt, and half the pepper. Spread them evenly on the sheet pan.

In the same bowl, combine the chicken thighs with the remaining olive oil, lemon juice, lemon zest, oregano, garlic, and remaining salt and pepper. Rub the seasoning mixture under and over the skin of each thigh. Nestle the seasoned chicken thighs among the potatoes, skin-side up.

Pour the chicken broth around the vegetables (not over the chicken to keep the skin crispy). Roast for 35-45 minutes, until the chicken skin is golden brown and crispy, the internal temperature reaches 165°F, and the potatoes are tender and golden.

Remove from the oven and let rest for 5 minutes. Sprinkle with fresh parsley and serve with lemon wedges. This rustic, satisfying meal embodies the comfort and warmth of traditional Greek family cooking.