Heat a 2-quart saucepan over medium-high heat and add the olive oil. When hot, add the hot dogs and cook, stirring occasionally, until the hot dogs are caramelized on both sides, about 3 minutes. Remove the hot dogs from the pan and set aside. Add the garlic and onions to the pan and cook, stirring occasionally, until the onions are wilted and the garlic is fragrant, 4 to 5 minutes. Add the thyme and sage to the pan and saute for 1 minute. Add the potatoes, chicken stock, salt, pepper and bay leaf to the pan and bring to a boil. Reduce the heat to a simmer and cook until the potatoes are tender, about 20 minutes. Remove the bay leaf and, using an immersion blender (or in batches using a bar blender), puree the soup until smooth. Return the hot dogs to the soup and add the tomatoes, heavy cream and chopped parsley. Rewarm gently, if necessary, and serve.