Preheat your oven to 400°F (200°C). Slice off the top of the head of garlic to expose the cloves. Drizzle with a teaspoon of olive oil, wrap in foil, and roast for about 30-35 minutes until soft and golden. Once cooled, squeeze the roasted garlic cloves out of their skins.
While the garlic roasts, dice the zucchinis into small pieces. Place them on a baking sheet, drizzle with a little olive oil, and sprinkle with salt. Roast in the oven alongside the garlic for about 15-20 minutes until tender and slightly caramelized.
In a food processor or high-powered blender, combine the roasted zucchini, roasted garlic cloves, chickpeas, tahini, lemon juice, olive oil, and ground cumin. Blend until smooth and creamy. If the mixture is too thick, add a tablespoon or two of water or reserved chickpea liquid to reach your desired consistency.
Taste your hummus and season with salt and pepper accordingly. Blend again briefly to incorporate the seasoning.
Transfer the hummus into a serving bowl. Drizzle a little olive oil over the top and sprinkle with freshly chopped parsley. Serve with warm pita bread, fresh vegetables, or your favorite crackers.