Preheat the oven to 425°F (220°C).

In a mixing bowl, combine unsalted butter, kosher salt, minced garlic, dried oregano, and coarse black pepper until creamy.

Pat the half chicken dry and rub the herb butter mixture thoroughly over and under the skin.

Squeeze fresh lemon juice over the chicken and season with additional kosher salt and black pepper to taste.

Place the chicken on a sheet pan and roast for about 50 minutes or until the internal temperature reaches 160°F (70°C).

Remove from the oven and let it rest for 10 minutes, covered loosely with foil.

In a food processor, combine parsley, red wine vinegar, roughly chopped garlic, oregano, crushed red pepper, kosher salt, and black pepper. Pulse until chunky, then drizzle in olive oil while processing.

Top the chicken with chimichurri and sprinkle feta cheese if desired. Serve immediately.