This is a dish best made in company. Coring vegetables can be onerous if done alone but is downright festive when many hands are at work together.
Some prefer to substitute medium-grain bulgur for the rice in this classic dish. A mix of the two grains can also be used.
Choose the smallest squashes available and very taut eggplants. Do not be tempted to substitute dark-green zucchini for the pale-skinned koosa: they tend to get too soft when boiled.