Preheat the oven to 200˚C/400˚F/gas mark 6.
Place the tomatoes on a baking tray. Season, sprinkle over the sugar and drizzle with the balsamic vinegar and half the oil. Roast in the oven for 20 minutes and set aside to cool.
Place the tomatoes, red peppers, chilli, garlic and smoked paprika into a blender along with the remaining oil, season and blitz to a coarse sauce.
Place the grated vegetables in the centre of a clean tea towel, pull the edges together and squeeze out all the excess liquid from the veg. Place in a large bowl, and stir in the white pepper, garlic powder, lemon juice and 1 tablespoon of the oil. Stir well to incorporate.
Heat the remaining oil in a medium pan. Shape the vegetable mixture into individual patties using your hands and add to the pan. Cook over a medium heat for 5–10 minutes or until they begin to brown on the underside, lifting gently with a spatula to check. Carefully flip over the röstis to cook on the other side.
Once they have browned on the other side (this will take a further 5–10 minutes), serve hot with the salsa and a sprinkling of freshly chopped parsley.