Prep the chicken: Pat the chicken dry with paper towels. This helps it sear well.
Season both sides with salt, pepper, smoked paprika, and garlic powder.
Heat the pan: Place a large skillet over medium-high heat. Add the olive oil and 1 tablespoon butter. When the fat shimmers and the butter foams, you’re ready to sear.
Sear the chicken: Add the chicken in a single layer.
Don’t crowd the pan. Sear for 4–5 minutes per side for thighs, or 3–4 minutes per side for thin breast cutlets, until golden brown. Transfer to a plate.
The chicken will finish cooking in the sauce.
Sauté the garlic: Lower the heat to medium. Add 2 tablespoons butter to the pan. When melted, add the minced garlic.
Cook for 30–45 seconds, stirring constantly, until fragrant. Do not brown the garlic.
Build the sauce: Pour in the chicken broth and scrape up the browned bits on the bottom of the pan. Add red pepper flakes if using. Simmer for 2–3 minutes to reduce slightly.
Finish with butter and lemon: Stir in the remaining 1 tablespoon butter and the lemon juice.
Taste and adjust salt and pepper. The sauce should be bright, buttery, and savory.
Return the chicken: Nestle the chicken back into the skillet. Spoon sauce over the top.
Simmer on low for 3–5 minutes, until the chicken is cooked through (internal temperature reaches 165°F/74°C).
Add herbs (and Parmesan if using): Sprinkle with parsley and swirl in Parmesan if you want a slightly creamier, richer finish.
Rest and serve: Turn off the heat and let the chicken rest in the sauce for 2–3 minutes. Serve with extra lemon on the side and spoon plenty of garlic butter over each piece.