Preheat oven to 400 degrees. In a mixing bowl, combine the garlic, herbs and drizzle of olive oil together. Season with salt and pepper. Mix thoroughly. Split the eggplant in half, lengthwise and smear the garlic mixture over the top of each eggplant half. Place the eggplant on a baking sheet and place in the oven. Roast the eggplant for 30 minutes or until the eggplant is tender. Remove from the oven and cool. Using a spoon, remove the flesh of the eggplant and discard the skin. Heat the oil in a 2 quart saucepan. When the oil is hot, add the onions. Saute for 2 minutes. Add the roasted eggplant and garlic and continue to saute for 2 minutes. Stir in the stock and bring the liquid to a boil. Reduce to a simmer and cook for 10 minutes. Using a hand-held blender, puree the soup until smooth. Stir in the cream and continue to simmer for 3 minutes. Season the soup with the salt and the cayenne.