In a small bowl, combine the olive oil, Dijon mustard, crushed garlic, lemon juice, lemon zest, and thyme. Season well.
Pat the chicken breasts dry with a paper towel and rub the marinade generously over the chicken, making sure to coat both the skin and the underside, leaving a tablespoon of marinade for basting. Leave the chicken to marinate for at least 10 minutes (or overnight in the fridge if you are making ahead)
Place the chicken breasts, skin-side up, in the air fryer basket. Make sure there’s space between them for even cooking.
Air fry the chicken breasts for 25–30 minutes, depending on their size. Halfway through cooking, check the chicken and baste it with your remaining marinade. The chicken is done when the skin is crispy, golden brown, and the internal temperature reaches 75°C
Let the chicken rest for 5 minutes before serving and serve with mashed potatoes and green beans.
Coated with a flavourful marinade of lemon, garlic, Dijon mustard and thyme, pop these chicken breasts in your air fryer for tender meat and crispy skin.