Step 1

Place the water, chickpeas, and baking soda in a 2 1/2-quart slow cooker. Cover and cook until tender, on high heat for 4 hours or on low heat for 8 to 9 hours. Drain and set aside.

Step 2

Place the chickpeas in the bowl of a food processor along with the garlic, salt and cumin. Process for 20 to 30 seconds. Scrape down the sides of the bowl, add the tahini and process for another 15 seconds.

Step 3

Add the lemon juice and 1/4 cup of the reserved bean liquid and process for 20 seconds, then scrape down the sides of the bowl. With the processor running, drizzle in the olive oil and process another 20 seconds or until smooth.

Step 4

To serve, transfer the hummus to a bowl and drizzle with additional olive oil and sprinkle with sumac or smoked paprika if desired.