Preheat oven to 180 deg Celcius (350 deg F).
Prepare the couscous according to packet directions, using the absorption method. When the water has been absorbed, fluff the couscous up with a fork and mix through the tablespoon of butter or olive oil. Set aside.
Trim the chicken fillets to remove any excess fat, and remove skin if necessary. Rub both sides of the chicken fillets with the additional olive oil and sprinkle the seasoning you have chosen over both sides of the fillets.
Lay the fillets flat in a baking tray or roasting pan (I normally line the tray with baking paper to make the clean-up process easier!).
Roast the fillets in the pre-heated oven for 15-20 minutes or until the chicken is cooked through (pierce the thickest piece with a skewer to check the juices run clear). The cooking time may vary slightly depending on the thickness of the fillets.
While the chicken is cooking, dice the tomato, cucumber and avocado, and soak the sultanas in boiling water (enough to cover) for approx 5 minutes, then drain.
Squeeze the lemon juice into the prepared couscous and mix through evenly.
Stir the tomato, cucumber, avocado and sultanas through the couscous.
To serve: spoon couscous onto plates for four people. Slice the cooked chicken on the diagonal and lay on top of the couscous. Any juices from the cooking process can also be spooned onto the chicken and couscous.
This can also be served on a bed of salad greens ie rocket, spinach or any crisp lettuce.