If you're cooking your chickpeas from scratch, all your spices, lemon, onion and garlic clove and cook until tender. Add the 1/2 tsp of baking soda towards the end
if you're using canned chickpeas, add them into a small pot with water covering the chickpeas. Add in your baking soda and cook for 10 minutes.
In a food processor, add in all your ingredients except spinach
Blend all your ingredients until smooth. Taste for salt, lemon
Add in your spinach and pulse 4 times. If you want it to be blended completely then keep blending. If you like the chunky spinach look pulse less.