Preheat oven to 350 °F.
Cut the top off of the head of garlic and place cut side down on a pan and drizzle with 1 tsp of olive oil. Bake for 20- 30 minutes or until garlic is soft. Let cool. Once cool, squeeze out the garlic from each clove.
Cook onion in 1 Tablespoon olive oil in a large skillet over medium high heat. Stir the onion frequently until they begin to brown. Reduce the heat to low and continue to cook until the onions are soft and a medium brown color.
Rinse and drain chickpeas reserving 3 Tablespoons chickpea liquid. Add chickpeas, liquid, lemon juice, tahini, garlic, salt, 3 Tablespoons olive oil, and onions to a food processor or high powered blender. Blend together until everything is combined and hummus is smooth.
Serve with pita bread, veggies, or crackers.