
Preheat oven to 400 degrees Fahrenheit. Bake the sweet potato on the middle oven rack or in a baking dish for 45 minutes to 1 hour. It will yield to a gentle squeeze when it’s done baking.
While the sweet potato is cooling, combine the tahini, garlic, lemon zest and juice, salt and cumin in a food processor. While processing the mixture, drizzle in 1 tablespoon of the water. Blend until the mixture is super creamy, pausing to scrape down the bottom or sides as necessary (you may need to add 1 to 2 more tablespoons of water if your tahini was thick).
Add the drained chickpeas and process until the mixture is completely smooth, about 2 minutes. Once the sweet potato has cooled enough to handle, use a knife or your fingers to peel off the skin. Discard the skin and add the sweet potato flesh to the food processor.
Blend until the mixture is completely smooth, about 1 minute. Taste, and blend in a pinch or two of cayenne pepper if you’d like your hummus to taste spicy. Enjoy as is, or garnish it with a drizzle of olive oil, a light sprinkle of cayenne pepper or sesame seeds. This hummus will keep well in the refrigerator for about 1 week.