Dice chicken breasts into bite-sized pieces and season with salt and pepper.
In a large skillet heat oil over medium-high heat. Add the chicken, turning every 2-3 minutes until all sides are browned and almost cooked through. Avoid overcrowding the pan, and cook in batches if necessary.
Add the butter and garlic and continue cooking until the chicken reaches 165℉ and the garlic is fragrant. If using, stir in fresh chopped parsley and serve.
Notes
Refrigerate leftovers for up to 4 days, or freeze for up to 1 month.