For the dough: Mix then instant dry yeast with the water and let stand.
Combine flour and salt then. Add the olive oil and water-yeast mixture.
Work for about 10 minutes, until the dough is soft.
To make it rise in place dry bowl, covered the bowl with a clean cloth and leave it a warm room for an hour. Once the dough has lifted, spread very thinly. Place on baking paper.
Preheat the oven to 500F or the highest temperature possible.
Place a pizza stone in a cold oven. Otherwise you can line a baking sheet with parchment paper. Place a baking tray on the bottom level. The goal is to get it preheated.
Filling: In a small bowl, whisk together Greek yoghurt, cream, salt, pepper and nutmeg
Cut the squash into thin slices and remove the peel. Do the same with the onion.
Spread the yogurt mixture on the dough. Leave a small border around the edge Scatter the onions on top, then the squash. Season with salt and pepper
Slide the rolled-out pastry dough onto the preheated pizza stone/baking tray. Place the baking tray at bottom level. If you're using a baking tray, remove the parchment paper after 3-4 minutes of backing otherwise it will burn.
Bake for 15 minutes, or until the edges are golden and the bottom is crisp. Set on grill for a couple of minutes .
Remove from the oven and top with arugula leaves and some olive oil