Roast then peel one bulb of garlic. You can store it in the fridge for a few days, if necessary. Set aside until you’re ready to puree everything together.
If cooking your beans, soak them overnight. Once they’re soaked, place them with the baking soda, the other bulb of garlic and enough water to cover them in a large saucepan. Beans should be covered with enough water to allow them to double in size. Cook them over medium high heat for 30-45 minutes, skimming the foam frequently. They are done when they are very soft. It doesn’t matter if they break apart a bit, since they’ll be whizzed up as much as possible in the food processor, but you don’t want mush.
Discard the garlic bulb from the bean pot and drain the beans.
Tip them into your food processor and process for at least two to four minutes, until they form a thick paste. Add the tahini and the garlic and process until the mixture is very creamy. Add the preserved lemon and process until the mixture is uniform and looks like thick hummus. If your lemons were “almost quartered” you might want to break them up a bit, depending on the strength of your food processor. Mine easily obliterates a whole lemon.
Very slowly add 180ml of the ice water to the mix while your processor is turned on. Let the food processor go to work for 3-4 minutes, then check the consistency of the hummus. You should be left with a gorgeous, silky texture.
Drizzle with olive oil to serve.
