If the chicken breasts are thick, slice them horizontally or pound them to an even thickness of about 1/2 inch. Season both sides with the divided kosher salt and black pepper.

Lightly coat each chicken breast in all-purpose flour, then shake off the excess. The thin coating helps the chicken brown and gives the sauce a little body.

Heat the olive oil and 2 tablespoons unsalted butter in a large skillet over medium-high heat. Add the chicken and sear for approximately 4–5 minutes per side, until golden brown and nearly cooked through.

Transfer the chicken to a plate and reduce the skillet heat to medium. Add the minced garlic and cook for 30–60 seconds, stirring constantly, until fragrant but not browned.

Pour in the chicken broth and fresh lemon juice, scraping up the browned bits from the bottom of the skillet. Add the lemon zest; if using wine, add it before the broth and simmer for 1–2 minutes.

Simmer the sauce for 3–5 minutes, allowing it to reduce slightly. For a creamy variation, stir in the optional heavy cream during this stage.

Return the chicken and any accumulated juices to the skillet. Simmer for another 2–4 minutes, turning the chicken once, until it reaches 165°F internally.

Remove the skillet from the heat and swirl in the remaining 2 tablespoons butter. Finish with the chopped parsley and taste for seasoning.

Serve the chicken immediately with spoonfuls of lemon garlic sauce and optional lemon slices. Pair it with rice, mashed potatoes, pasta, crusty bread, or a green vegetable.