Preheat oven to 375 degrees.
Cut eggplant in half lengthwise, and brush with the olive oil. Place on baking sheet lined with parchment paper. Score the cut side of eggplant with sharp knife and bake cut side down for about 1 hour or until lightly browned and flesh is soft. Remove and cool slightly.
While the eggplant is roasting, in a large pot, brown sausages in olive oil. Cook sausages on high heat for about 5 minutes, turning frequently. Remove and set aside.
Add the onions, garlic and leeks and saute for 8 to 10 minutes on medium heat until golden and very soft.
Add the tomatoes, tomato paste, herbs, bay leaves and stock. Simmer uncovered for about 30 minutes.
Add the roasted yellow pepper and continue to simmer for a further 10 minutes.
Scrape the flesh from eggplant and pulse in food processor. Remove bay leaves from stock mixture. Add it into the puree. Pulse until smooth.
Return the whole mixture back to the pot and simmer gently for a few minutes. Adjust seasoning and add the cream. Bring to a boil then remove from heat.
Before serving finish cooking sausage in oven for several minutes or until no longer pink inside. Serve several slices of sausage in a bowl and cover with the soup.