Step 1

Pour the chickpeas into a large bowl; cover them with several inches of water. Let soak at room temperature overnight. (Alternatively, cover the chickpeas with boiling water and let soak for an hour.) Drain and pat dry.

Step 2

Transfer the chickpeas to a large pot over medium heat, sprinkle with the baking soda and stir to coat. Warm them, stirring, for 3 minutes, then cover by several inches with cool water.

Step 3

Increase the heat to high; once the liquid comes to a boil, reduce the heat to medium-low or until the water is gently bubbling. Cook the chickpeas until soft, from 45 minutes up to an hour or two. Remove from the heat and vigorously stir the chickpeas to loosen the skins. Tilt the pot to one side and use a skimmer or slotted spoon to skim off as many of the loosened skins as you can, stirring occasionally to get them to float. Carefully pour off the cooking water through a strainer into a bowl, catching more skins and reserving 1 cup of the cooking liquid. Remove any remaining skins by gently rubbing them off between your fingers. Discard the skins. You should have 2 cups of cooked, peeled chickpeas; reserve any extra for another use.

Step 4

Chill the chickpea cooking liquid for at least 2 hours.

Step 5

Cut the garlic clove in half lengthwise. If there is a green sprout, cut it out and discard it. Mince the garlic and transfer it to a food processor along with the cooked chickpeas. Process for a few minutes to form a very thick, smooth paste.

Step 6

With the machine running, gradually add the tahini, the 1/2 teaspoon of salt and the 2 tablespoons of lemon juice, processing until well incorporated and stopping to scrape down the sides of the bowl as needed. Continue to puree; gradually add the chilled chickpea cooking liquid a tablespoon at a time, processing until the hummus has lightened. (You will probably use between 1/3 and 2/3 cup of the liquid.) Taste the hummus as you go, adding salt and/or lemon juice as needed but taking care not to add too much of the latter so the hummus stays thick.

Step 7

To serve, spoon the hummus into a shallow soup bowl or medium plate. Use the back of the spoon to create a well in the center with a deep rim of hummus around the edge, turning the plate as you go. Drizzle generously with oil and sprinkle with the ground sumac or paprika.

Step 8

NOTE: To use canned chickpeas, drain and pat dry 2 cups of chickpeas, reserving and chilling the can liquid for making the hummus, then stir in the baking soda. Warm the coated chickpeas on the stove top, then rinse in a large bowl, changing the water three times. With each rinse, rub the chickpeas vigorously, and the skins will fall off and rinse away.