For the hummus:
- Combine beans, 2 teaspoons baking soda, and 6 cups water in large bowl and refrigerate 12 hours.
- Drain beans and place them in a large sauce pan. Add 10 cups water, garlic, and 1 teaspoon baking soda. Bring to a simmer over medium heat, then cover and cook for 1 hour, stirring approximately every 20 minutes. Beans should be just splitting apart and have a very creamy texture.Drain excess liquid from pan into a bowl and reserve. Place beans and garlic in a food processor while warm and purée for 15 minutes.
- While food processor is running, add reserved cooking liquid, lemon juice, cumin, and salt. Process until very smooth. Slowly stream in tahini and then olive oil. Hummus should be light and airy. Note: Hummus is best served warm that day, but can be refrigerated for up to 2 days.
- To plate, place approximately 1 cup hummus on a plate and use large spoon to make a well in center. Pour ¼ cup of thinned tahini sauce into the center of the well. Garnish with chopped parsley and drizzle of extra virgin olive oil.
For the tahini sauce:
- In the bowl of a stand mixer fitted with whisk attachment, whip tahini for 5 minutes on high speed.
- With mixer running, slowly add lemon juice then drizzle cold water and salt into bowl. Occasionally stop mixer and scrape sides with a rubber spatula to ensure even mixing.
- To thin sauce before drizzling over hummus, add an additional ¼ cup cold water to tahini.
For the garlic lemon juice:
Crush unpeeled garlic cloves with a knife. Add to a blender along with lemon juice. Blend on highest setting for 3 minutes. Once blended, let mixture rest for 30 minutes, then strain through a fine mesh strainer.