Cut the chicken into bite-size pieces. Add the chicken to a bowl and season with salt & pepper and the garlic powder, then sprinkle the cornstarch over it. Toss until coated.
Add the olive oil and 1 tablespoon of the butter to a skillet over medium-high heat.
Once the pan is nice and hot, add half of the chicken to the skillet and ensure each piece isn't crowded so it browns properly. Cook for 4 minutes and then flip and cook another 3-4 minutes or so using cooking tongs. Chicken should be browned and cooked through (165F).
For the second batch, you may need to add another splash of olive oil (up to 1 tablespoon) to the pan if it's looking dry. Transfer the chicken to a plate once it's done.
Take the skillet off the burner and let the pan cool for about one minute, then add the remaining butter and garlic to the skillet. Cook, stirring almost constantly, for 1-2 minutes or until the garlic is cooked.
Add the chicken back in and toss with the butter sauce. Serve immediately with parsley sprinkled over top.
