Heat 2 tablespoons of oil in a heavy large pot over medium-high heat. Add the onions, carrots, garlic, and thyme and saute until the onions are translucent, about 5 Minutes.
Add the broth, peppers, potato, wine, chilli sauce you've chosen and the sugar. Bring to a simmer over high heat. Decrease the heat to medium-low. Partially cover and simmer until the potatoes are very tender, stirring now and then, about 30 Minutes.
Using a hand blender, purée the soup in the pot until it is smooth. Season the soup, to taste, with salt and pepper.
Serve the soup into bowls. Dollop a tablespoon of mascarpone in the centre of each bowl and top.