To roast the vegetables, place the onions, tomatoes, garlic, and bell peppers in an oven tray and season with salt and pepper. Drizzle with little olive oil and balsamic vinegar, and roast in a 180c degrees oven for 40 minutes.
Leave the vegetables to slightly cool, and peel the tomatoes and bell peppers.
Place all the content of the roasted and peeled vegetables in a pot on medium heat. (including any accumulated juices).
Add Knorr Vegetable Stock cube and stir together until combined with ingredients. Add the warm water, tomato paste, sugar, fresh thyme, and a pinch of hot chili powder, and season with more salt and pepper if needed. Let boil for 10 to 15 minutes.
In a blender (or hand blender), process the soup until smooth and return to heat. Add the orzo pasta and let boil for few minutes until pasta is tender.
Add the fresh cream and let boil for 2 to 3 minutes.