Step 1Preheat the oven to 200 °C/ 400 °F (fan assisted), or 220 °C/ 425 °F (conventional). Cut the peppers in half and remove the core with the seeds. Lay the peppers cut side down on a baking sheet lined with parchment paper and place in the oven. Roast the peppers for about 20 minutes or until the skin blisters and starts turning black.