Sift the chickpea flour into a large bowl and gradually add the water, whisking continuously to avoid lumps.
Remove any foam that forms on the surface and leave the batter to rest for 4 hours.
Thinly slice the regular onion and spring onions and set aside.
Add the olive oil and salt to the batter and give everything another good mix.
Pour the batter into your baking tray, evenly distribute the sliced onions on top, and bake for approximately 25 minutes at the highest temperature your home oven allows (ideally 250–270°C), until golden and crispy.
