Oven Method - Heat the oven to 180 degrees C. Place the bell peppers on a baking tray and roast the bell peppers till their skin turns black (25-30 mins approximately). Once done, take it out and let to cool down. Peel the charred skin, chop and use to make hummus.  Gas Flame Method - You can directly roast it on the flame using a tong until the skin is charred. Once done, keep it aside to cool down. Peel the charred skin, chop and use to make hummus. You can even use your BBQ to roast the peppers.