Step 1

Place a rack in upper third of oven and preheat to 375°. Scatter sweet potato and garlic across a parchment-lined baking sheet, generously drizzle with oil, and toss to coat. Roast, tossing halfway through, until garlic is golden brown and sweet potato is tender and browned in a few spots, 40–45 minutes.

Step 2

Let vegetables cool slightly, then transfer to a food processor or blender and purée until smooth. Add tahini and 1½ tsp. salt and squeeze in juice from lime; pulse to incorporate. With motor running, gradually add 1 cup water. Mixture should be the consistency of hummus; add a little more water if needed. Taste and season with more salt if needed.

Step 3

Do Ahead: Hummus can be made 3 ahead. Cover and chill. Bring to room temperature before serving.