Quarter and core the 6 peppers and place them skin side up on a baking sheet lined with baking paper. Roast at 200°C (392°F) on the top shelf, or place on a preheated grill, for 20-25 minutes until the skins are completely blackened. Remove from heat, cover with a damp tea towel, and let cool for 10-15 minutes until you can handle them comfortably.
While the peppers roast, finely dice the red onion and transfer to a bowl. Add ½ teaspoon honey, 4 teaspoons lemon juice, and 4 tablespoons olive oil. Mix well to combine, then season with salt and pepper to taste.
Peel the charred skin off the cooled peppers and discard. Halve the pepper pieces if they are too large. Add them to the dressing, mix well, and let steep for at least 30 minutes before serving.