Place each chicken breast between two sheets of plastic wrap or parchment paper and pound gently with a meat mallet or rolling pin until about 1.5 cm thick, creating an even surface for cooking.
Pat the chicken dry with paper towels to remove excess moisture, ensuring a crisp sear.
In a small bowl, mix salt, pepper, and smoked paprika. Season the chicken generously on both sides with this spice blend, pressing it into the meat.
Heat a cast-iron skillet over medium-high heat until shimmering and hot, about 3 minutes, with a gentle sizzle when oil is added.
Add olive oil to the pan, swirling to coat the bottom evenly. Carefully lay the chicken breasts in the pan, listening for a satisfying sizzle.
Let the chicken cook undisturbed for 4-5 minutes, observing a golden-brown crust form at the edges and underneath, with a fragrant aroma filling the air.
Flip the chicken using tongs and cook for another 4 minutes, checking that the internal temperature reaches 75°C (165°F) with a meat thermometer for perfect doneness.
Add a tablespoon of butter and a sprig of thyme to the pan, then tilt the pan slightly to spoon the melted butter over the chicken, basting it for flavor and moisture.
Remove the chicken from the pan and transfer to a plate. Let it rest for 5 minutes to allow juices to redistribute, keeping each bite juicy.
While resting, squeeze fresh lemon juice over the chicken and sprinkle with lemon zest for bright, zesty flavor.
Slice the chicken against the grain to serve, revealing a juicy interior with a crisp, golden exterior—ready to enjoy!
