Step 1

Combine chickpeas, 1 teaspoon (6g) baking soda, and 2 tablespoons (24g) salt in a large bowl. Cover with 6 cups (1.4L) cold water. Stir to dissolve salt and baking soda. Let stand at room temperature overnight. Drain and rinse chickpeas thoroughly.

Step 2

Place chickpeas in a large Dutch oven or saucepan. Add remaining baking soda, 1 tablespoon (12g) salt, onion, celery, carrot, garlic, bay leaves, and rosemary, if using. Add 6 cups (1.4L) water and bring to a boil over high heat. Reduce to a simmer, cover with lid slightly cracked, and cook until chickpeas are completely tender and nearly falling apart, about 1 hour 30 minutes. Check on chickpeas occasionally and top up with more water if necessary; they should be completely submerged at all times. Let cool slightly.

Step 3

Discard onion, garlic, celery, carrot, bay leaves, and rosemary. Drain chickpeas, reserving their cooking water.

Step 4

In a blender or food processor, combine 1 cup (235ml) tahini sauce with about one-quarter of the cooked chickpeas and blend until very smooth, with a thick but pourable milkshake-like consistency. Thin with a little of the reserved cooking liquid if necessary (but be careful not to thin too much at once; you can always thin more, but can't remove liquid once it's added). Season with salt.

Step 5

In a mixing bowl, combine tahini mixture with remaining chickpeas and parsley. Stir until thoroughly mixed and chickpeas are coated in a creamy sauce. (If you prefer the sauce thinner, gently work in a little more of the reserved cooking liquid.) You can refrigerate the hummus at this point; it will become thicker in the refrigerator.

Step 6

Spoon onto a serving dish, drizzle with olive oil, and top with garnishes of your choice. Serve with warm pita bread.