Preheat the oven to 190°C/gas 5. Lay the peppers one at a time on a chopping board and cut a T shape into them, with the long part of the T running parallel with the stalk and the top of the T at the thickest part of the pepper. Gently poke your fingers or a small knife into the pepper to remove the seeds and fibres. Poke one-sixth each of the tomato wedges, herbs and garlic slices into the pepper, trying to avoid breaking it as they will spill out if the skin breaks open. Repeat with the other peppers and remaining tomato wedges, herbs and garlic.
Place the stuffed peppers in a roasting dish and drizzle with the olive oil and plenty of salt and pepper. Bake until the skin begins to blister, but before they darken too much, about 20–25 minutes. Remove from the oven and leave to cool.
These are best eaten at room temperature, but will keep covered in the fridge for up to 2 days.