In a large bowl, soak 4 cups of chickpeas in water overnight or for at least 8 hours. This will help soften them and make them easier to blend.

Drain the soaked chickpeas and place them in a large pot. Pour enough water to cover them, and add 2 teaspoons of baking soda. Bring to a boil and let the chickpeas cook for about an hour, or until they are soft and can be easily mashed with a fork.

While the chickpeas are cooking, prepare the olive tapenade by blending together 18 kalamata olives, 2 small chopped onions, 5 tablespoons of lemon juice, and 5 tablespoons of olive oil in a food processor or blender. Set aside.

Once the chickpeas are cooked, drain them and let them cool for a few minutes. Then transfer them to a food processor or blender along with 4 tablespoons of tahini, 15 garlic cloves, 4 tablespoons of chicken bouillon powder, and salt according to taste. Blend until smooth and creamy.

Scoop out about half of the blended chickpea mixture into a bowl, and mix in the prepared olive tapenade. This will give the hummus its signature marbled look and added flavor.

Transfer the olive tapenade hummus to a serving bowl and drizzle with olive oil. Serve with pita bread, raw vegetables, or crackers for dipping.