Alianthos ( witch is the ancient Greek name for the area)is a relatively newcomer to the Varkiza even though the owners had a fabulous little restaurant/taverna on a small square in the area for many years.
Is on the main promenade of Varkiza with great views of the sea and excellent food.Specially the fresh fish bought from the small fishing port's market 100 meters away from it.
The service is always great (and with a smile) and the food is excellent and above all very very reasonable. Their chips are the best I have tasted, probably because they are from freshly cut potatoes and not frosen ones and cooked in their own olive oil from small local producers. Try their wines.Their own carafe is excellent and great value.If you feel more adventurous have an excellent Sauvignon Blanc they stock called "Magiki Plagia" (Magic Mountainside) witch at under 20 euros is one of the best i have tasted.
Well worth a visit.