Mix together the sauce ingredients in a small bowl and set aside.
Heat oil over medium high in a wok or frying pan. Add garlic slices and stir for 1 minute until the oil is fragrant. Remove the garlic cloves and discard.
Add pepper and onion back into pan and combine with the meat. Add in basil leaves and cook for 1 minute. Add the sauce to the pan and cook for 2-5 minutes until mixture is well coated and the sauce is well absorbed. Serve immediately.