Prep the chicken: Pat the chicken pieces dry with paper towels.
Dry chicken browns better and prevents steaming.
Season generously: In a bowl, toss chicken with salt, pepper, garlic powder, smoked paprika, and red pepper flakes if using. Coat evenly.
Heat the pan: Set a large skillet over medium-high heat and add the avocado oil. Give it a minute to get hot—the oil should shimmer.
Sear in batches: Add half the chicken in a single layer.
Don’t overcrowd. Cook 3–4 minutes without moving, until golden on one side, then flip and cook another 2–3 minutes until cooked through. Transfer to a plate and repeat with the remaining chicken.
Make the garlic butter: Reduce heat to medium.
Add the butter to the empty skillet. Once melted and foamy, add minced garlic. Stir for 30–45 seconds until fragrant.
Avoid browning the garlic.
Deglaze and brighten: Add lemon juice to the pan and scrape up the browned bits. Those bits are pure flavor.
Toss it all together: Return the chicken to the skillet. Stir to coat every piece in the garlic butter sauce.
Cook 1 minute to warm through.
Finish and serve: Turn off the heat. Stir in parsley and, if using, Parmesan. Taste and adjust salt, pepper, or lemon.
Serve hot with your favorite low-carb side.