Wash the thyme, remove the leaves. Mix with olive oil, lemon pepper and herbs from Provence. Wash the meat and pat dry. Set aside 5 tablespoons of marinade. Mix the rest of the marinade and the meat.
Cover and leave to cool for at least 3 hours.
Peel and finely grate the onion. Mix with steak sauce, sugar and whisky. Stir in sunflower oil and wash and slice the tomatoes. Clean, wash and drain the lettuce.
Grill the meat on the hot grill for 10-12 minutes. Coat several times with the remaining marinade. Season meat with salt.
Warm the flatbread and cut it into cake pieces. Cut in from the top. Cut the chicken fillets into slices. Arrange in bread with onion-steak sauce, tomatoes and salad.