Season chicken breasts uniformly on both sides with salt and black pepper.
Heat olive oil in a large heavy-bottomed skillet over medium-high heat until shimmering.
Place chicken in the skillet and sear for 5 to 7 minutes per side, or until the internal temperature reaches 165 degrees Fahrenheit and the exterior is golden brown.
Remove chicken from the skillet and transfer to a warm plate; cover loosely with foil.
Add minced garlic to the remaining fat in the skillet and sauté for 60 seconds until fragrant but not browned.
Pour in the chicken broth and lemon juice, using a spatula to deglaze the pan by scraping up the fond (browned bits).
Simmer the liquid for 3 to 5 minutes over medium heat until the volume has reduced by approximately half.
Reduce heat to low and whisk in the cold butter one tablespoon at a time until the sauce is emulsified and glossy.
Return the chicken and lemon slices to the skillet, spooning the sauce over the meat for 2 minutes to reheat.
Garnish with chopped parsley and serve immediately.