Preheat oven to 400 degrees.
In small castiron skillet lightly toast the cumin seeds until they start turning fragrant, about 3-5 minutes. DO NOT burn! Set aside.
On an ungreased baking sheet arrange the bell pepper quarters skin side up. Roast for about 20 minutes or until the skin starts to blister and char.
Remove peppers from oven and immediately place the peppers in a paper bag to "sweat". Close bag tightly and let stand for 20 minutes.
Meanwhile, in a food processor or blender combine the garbanzo beans and broth, processing until smooth.
Next remove the skin, seeds and membrane from the bell peppers and add to the food processor along with the lemon juice, tahini, garlic and salt. If choosing to use ground cumin add it in, too, with the lemon juice, tahini, etc. If using whole cumin seeds, see Step #7. Process until very smooth. (Also, if the mixture seems too thick and won't blend well, start by adding a tablespoon or so of broth or garbanzo bean liquid).
Transfer the mixture to a serving bowl and add the toasted cumin seeds, scallions, and fresh cilantro. Stir well to combine.
Let stand at room temperature for 30 minutes. Adjust seasoning if necessary and garnish with suggested toppings if desired.