Begin by patting the chicken breasts dry with paper towels. Season both sides generously with coarse salt and freshly cracked pepper.
Place the flour in a shallow dish and dredge each chicken breast in the flour, ensuring they are coated evenly. Shake off any excess flour and set aside.
In a large skillet, heat the olive oil over medium-high heat. Once the oil is shimmering, it’s time to add the chicken.
Add the dredged chicken breasts to the skillet. Cook for about 4-5 minutes on each side, or until golden brown and cooked through (internal temperature should reach 165°F). Remove the chicken from the skillet and set aside on a plate.
In the same skillet, add the thinly sliced garlic cloves. Sauté for about 30 seconds, until fragrant, being careful not to burn them.
Pour in the chicken stock and stir to deglaze the skillet, scraping up any bits stuck to the bottom. Allow it to simmer for a minute before adding the lemon juice.
Stir in the unsalted butter until melted and the sauce is smooth. Adjust seasoning with salt and pepper as needed.
Place the seared chicken back into the skillet, spooning the lemon butter sauce over the top. Let it simmer for another minute to soak up the flavors.
Remove from heat and garnish with minced fresh parsley, if desired. Serve hot with your choice of side dishes.