Sauté the onions over a medium heat in the butter until soft.
Turn the heat up, add the chicken and sauté about 5 minutes.
Season with salt and pepper.
Add the zucchini and cook until they reach your desired level of tenderness and the chicken is fully cooked.
Add the cream, garlic and sun-dried tomato paste and cook for another 2 minutes.
Turn off the heat and stir in the fresh basil, leaving a little bit for garnish.
Garnish with the remaining fresh basil and some crumbed feta cheese.