Preheat the oven to 190°C fan (210°C/415°F/Gas 6–7). Place the cut peppers in a deep baking tray.
Mix the remaining vegetables with the freekeh in a large bowl and add half the passata. Season with half the salt and the pepper, and stir through the olive oil and herbs. Use a spoon to fill the pepper halves with the mixture.
Pour the rest of the passata around the peppers in the tray, adding about 360ml water and season with the remaining salt. Cover the tray tightly with foil – this will create steam inside to cook the freekeh.
Bake for about 35 minutes until the freekeh is cooked. Use a small teaspoon to try a bit of freekeh; if it needs more time, return the tray to the oven for another 5–10 minutes.
Serve with some of the warm tomato passata from the baking tray and a dollop of Greek-style soya yogurt or similar.
Tip: If you have any stuffing mixture left over, which often happens as peppers are different sizes, simply place it in a saucepan and add enough water to cover by 2.5cm. Cook over a medium heat for 15 minutes to make a lovely thick, grainy soup.