Peel off the outer layers of the garlic bulb, leaving the cloves intact. Cut off and discard the top 1/4 of the bulb; drizzle with 1 teaspoon olive oil and wrap tightly in aluminum foil.
Bake garlic in the preheated oven until softened, about 50 minutes.
Squeeze garlic cloves out of their papery skins. Place garlic, chickpeas, tahini, olive oil, lemon juice, ground cumin, salt, and black pepper together in a blender. Cover and puree until smooth. Garnish with more cumin.