Loosen skin from chicken and insets a lemon slice and some rosemary into each. Sprinkle with salt and pepper.
Heat a large cast-iron skillet (or other oven safe skillet) with about 3 Tbsp of oil over med-high heat. Place chicken skin side down and sear until lightly golden, about 10 minutes.
Place skillet in oven at 425°F and cook another 10 minutes. Flip chicken and cook another 10 minutes or until chicken is fully cooked.
If desired, for a quick pan sauce, remove chicken from skillet and place on stove top over med-high heat. Pour in about 1 cup of white wine into skillet, stirring with a wooden spoon to deglaze pan and loosen all the crusty bits from the bottom. Allow to simmer until liquid is reduced by half, then stir in about 1 Tbsp of cold butter. Whisk until dissolved and a creamy emulsification is formed. Pour over chicken and serve.