Soak the dried chickpeas overnight with the bicarbonate of soda.
Drain and rinse well, then cover with fresh water and simmer for 30–40 minutes, or until very soft and almost falling apart.
Drain well while still warm and transfer to a blender or food processor.
Add the tahini, lemon juice, sea salt and gradually add the iced water while blending until the hummus becomes light, smooth and fluffy.
Blend for 3-5 minutes, scraping down the sides if needed.
Spread onto a serving plate and finish with a drizzle of extra virgin olive oil and your favourite toppings.
