Defrost the large shrimp according to the package instructions if using frozen shrimp.
Heat the olive oil in a large skillet over medium heat.
Add the diced onion and minced garlic cloves and sauté for 2–3 minutes until fragrant and translucent.
Pour in the white wine or chicken broth and let it simmer for about 5 minutes to reduce slightly.
Add the shrimp to the skillet and cook for 2–3 minutes until pink and heated through.
Stir in the butter, fresh oregano, and fresh parsley until the butter melts and the sauce becomes smooth.
Season with the black pepper, stir well, and remove from heat.
Serve immediately.