Pat the chicken thighs completely dry with paper towels to remove excess moisture so they brown properly.

Combine the onion powder, paprika, salt, and pepper in a small bowl. Rub the chicken thighs generously with the seasoning mixture on both sides.

Arrange the green beans in a microwave-safe dish with 1/2 cup water and microwave for 8-10 minutes until almost done but still crisp.

Heat a large cast iron skillet over medium-low heat and melt 2 tablespoons of butter.

Place the seasoned chicken thighs top side down in the hot skillet and cook until golden, about 5-6 minutes. Flip and cook another 5-6 minutes until cooked through and internal temperature reaches 165°F (75°C). Transfer to a plate.

In the same skillet, lower the heat and melt the remaining tablespoon of butter. Add chopped parsley, garlic, hot sauce, red pepper flakes, and pre-cooked green beans. Cook for 4-5 minutes, stirring regularly.

Add lemon juice and chicken stock. Let the sauce reduce for a couple of minutes until slightly thickened.

Push green beans to the side, place the chicken back in the pan with the sauce, and reheat quickly. Adjust seasoning with additional pepper if needed.

Serve warm, garnished with more crushed chili pepper, fresh parsley, and a slice of lemon if desired.