Season chicken with salt and pepper.
Heat olive oil in a skillet and cook chicken 5–6 minutes per side until golden and cooked through, then remove.
Add butter and garlic to the skillet and sauté 30 seconds until fragrant.
Stir in ranch seasoning and chicken broth and simmer 2–3 minutes.
Add heavy cream and cream cheese and stir until smooth and creamy.
Return chicken to the skillet and spoon sauce over it.
Simmer 3–4 minutes until sauce thickens slightly.
Sprinkle cheddar on top if using and garnish with parsley before serving.