Mix the dressing - consisting of 4 tablespoons of olive oil, lemon juice, 2 tablespoons of orange juice, some mustard, brown sugar and some tomato seasoning salt - in a large bowl.
Halve and quarter the tomatoes. Then remove the green stem and cut in half again. Pour into the dressing. Peel the vegetable onion, dice it finely and add it to the bowl. Fold in everything well and put in a cool place.
Clean and halve the peppers. Free from the stem as well as from the inside. Brush all around with olive oil and place in the preheated oven for approx. 20 minutes at 200 ° C.
Fill the cooked pepper halves with the tomato salad and serve.