Preheat the oven to 200˚C.
Lightly oil a medium-sized baking dish and use the pastry to line the base. Cut the courgettes into medium-thickness round slices and place them in a bowl. Sprinkle the courgettes with salt to draw out the bitterness. Peel and cut the potatoes into thin round slices.
When the courgettes have drained, dredge them with flour and put a layer of them in the baking dish on top of the pastry. Sprinkle generously with the cheeses and mint and drizzle with oil. Next, top with a layer of potato slices, cheeses, salt and pepper and mint, and drizzle again with oil.
Continue to make layers with courgette, potatoes and MEVGAL cheeses until the ingredients are used up. For the final layer, drizzle the vegetables liberally with oil and then pour over the MEVGAL Strained Yoghurt. Put the baking dish in the oven bake for 1½ hours.