Cut off the stalk from the peppers and remove the seeds and white partitions from the pointed peppers with your finger. Then wash inside and outside and pat dry with kitchen paper.
Put aside.
Prepare the couscous according to the instructions on the packet, loosen up with a fork and allow to cool briefly.
Crumble the feta cheese with your hands and add it to the couscous together with garlic, 2 tablespoons of olive oil, olives and herbs and mix. Season with salt and pepper.
Fill the peppers with couscous-pecorino cheese mixture, place the lid on top and place a fireproof baking dish brushed with oil.
Heat 2 tablespoons of oil in a pan, sauté the onion, add the tomatoes and bring to the boil briefly. Season to taste with sugar, salt and pepper. Pour the tomato sauce over the peppers and cook covered in the preheated oven at 180°C for 40-50 minutes.