Using a large rimmed baking sheet/pan, evenly coat the tomatoes with about 3 tbsp. olive oil. Lightly season with salt and pepper and bake for about 40 minutes, until tomatoes are fragrant and noticeably blistered.
About 15 minutes before the tomatoes have finished roasting, heat the remaining oil in a heat bottomed stock pot, over medium high flame. When the oil is hot add the chopped onions and garlic - lightly season with salt and pepper. Reduce the flame to low and slowly cook the onions and garlic till they are golden brown.
After the tomatoes have finished roasting and the onions and garlic have brown sufficiently, add the tomatoes (including the juices!) to the pot of onions and garlic. Stir to combine then add chicken stock.
Add the basil, oregano, red pepper fakes and parmesan; bring the soup to a simmer and cook, undisturbed, for about 25 - 30 minutes, or until the mixture has greatly reduced.
Either blend the soup until smooth, using and immersion blender or in small batches by using a stand blender.