Preheat the oven to 400ºF. Scrub sweet potatoes and pierce in several places with a fork. Place the potatoes on a baking sheet that has been lined with aluminum foil.
Trim about 1/4 inch off the top of the garlic cloves. Drizzle 1 teaspoon of olive oil over the the garlic and wrap the garlic in aluminum foil. Place on the baking sheet with the sweet potatoes.
Bake for 45-60 minutes or until the potatoes are soft and starting to ooze. Remove the garlic at 45 minutes. When the potatoes are soft, remove from oven and let cool to room temperature.
When the potatoes are cool, remove the skin. Remove the garlic cloves from the foil and remove the skin. Place the sweet potatoes, garlic, olive oil, chickpeas, tahini, lemon juice, rosemary, salt, and pepper into a food processor. Blend until smooth. You might have to scrape down the sides and blend again. Taste and season with more salt and pepper, if necessary.
Spoon sweet potato hummus in a bowl. Garnish with feta cheese, pomegranate arils, and a sprig of rosemary. Serve with chips.
Note-you can roast the sweet potatoes and garlic a day in advance. Keep in the refrigerator in a Ziploc bag until ready to use. You can also make the hummus a day in advance, just wait to garnish until ready to serve.