Step 1

Hummus: Combine chickpeas and 1/2 teaspoon baking soda in a bowl. Add cold water to cover; soak overnight.

Step 2

Drain and rinse chickpeas; transfer to a large pot and add 3 quarts water. Add remaining 1/2 teaspoon baking soda; bring to a boil. Boil until chickpeas are tender but not mushy, 1 to 1 1/2 hours. Skim off any floating shells. Scoop out 1 cup; set aside. Continue cooking the rest until completely soft, about 20 minutes.

Step 3

Prepare an ice bath. Drain chickpeas and transfer to a bowl set in ice bath; let cool completely (or refrigerate, covered, up to overnight). Pick off any remaining skins (optional). Place chickpeas in a food processor with tahini, lemon juice, cumin, garlic, oil, and ice water; season with salt and pepper. Purée until smooth. If too thick, add remaining ice water, a bit at a time; purée until smooth. Season to taste.

Step 4

Tahini Sauce: Pour tahini into a medium bowl and add lemon juice. Mix with a fork or a whisk until color turns a shade lighter. Gradually whisk in about 1/2 cup icewater. The sauce should turn smooth, velvety, and almost white. Keep tinkering with water, lemon juice, and tahini until you get a consistency and flavor you like. Whisk in salt and garlic; taste and adjust seasonings. (Makes about 1 cup.)

Step 5

To serve hummus, gently reheat reserved cooked chickpeas in a small saucepan over medium. Spoon hummus into a shallow serving dish, leaving a crater in center. Add cooked chickpeas to crater; sprinkle with parsley, drizzle with oil, and lightly dust with paprika. Serve with tahini sauce and harissa.