Slice each chicken breast in half horizontally to create 4 thin cutlets, then pat dry.
Season both sides of the chicken with Italian seasoning, salt, black pepper, and crushed red pepper flakes if using.
Heat 1 tablespoon olive oil in a large skillet over medium-high heat until shimmering.
Add the chicken to the skillet and cook 3–4 minutes per side until golden and cooked through; remove chicken and set aside on a plate.
Lower the heat to medium-low and add 2 tablespoons butter to the same skillet. When melted, stir in the minced garlic, chopped parsley (or cilantro), and a pinch of crushed red pepper flakes.
Cook the sauce 1–2 minutes, stirring, until the garlic is fragrant and lightly golden but not burned.
Return the chicken to the skillet and spoon the garlic-butter sauce over it; heat for 1–2 minutes to warm through.
Serve immediately with your choice of pasta, vegetables, or rice.
