1. In a food processor purée chick-peas, tahini, lemon juice, oil, and garlic paste and, if a smoother texture is desired, force through a fine sieve into a bowl. Whisk in enough water to reach a pourable but still thick consistency and stir in parsley and salt to taste.
2. Cut broccoli stems into spears about 5 inches long with flowerets 1 1/2 inches wide. On a steamer rack set over boiling water steam broccoli, covered, until crisp-tender, about 4 minutes.
3. Serve broccoli topped with hummus.