Drain the cannellini beans.
Add ⅔ of the drained beans to a high speed blender along with the spinach, tahini, dill, parsley, cumin, mustard, stock cube and water. Blend until smooth then transfer to a saucepan. This is your soup base.
Add the remaining drained beans to the soup. Bring the soup to a simmer over a medium heat then cook for 5-10 mins.
Stir through a good glug of olive oil and the juice of ¾ the lemons, then season to taste with plenty of salt and pepper.
To serve, ladle the soup into bowls and top with a drizzle of za’atar and an extra drizzle of tahini and olive oil. Finish with a pinch of salt and pepper, and the zest and juice of the remaining lemon.
