In a large bowl, combine grated onion, garlic, lemon juice, olive oil, crushed red pepper, black pepper, paprika, salt, and finely chopped parsley. Mix well.
Add the chicken thighs and coat thoroughly with the marinade.
Cover and marinate for at least 30 minutes in the refrigerator. If you’re short on time, you can cook right away.
Heat a drizzle of olive oil in a large skillet or grill pan over medium-high heat.
Cook the chicken uncovered for 5–6 minutes per side, until golden and the internal temperature reaches 165°F / 74°C.
Grating the onion creates natural juices that tenderize the chicken and help the spices cling beautifully. Don’t skip this step. A food processor helps.
You can cook these on the stovetop, grill, or in the oven.