Heat the olive oil in a large pot over medium heat. Add the sausages and brown them on all sides. Remove the sausages and set them aside.
Add the onion, carrots, parsnips, and potatoes to the same pot. Cook for about 5 minutes, stirring occasionally, until the vegetables begin to soften.
Stir in the garlic and flour. Cook for 1 minute to remove the raw flour taste.
Pour in the Guinness and beef broth. Add the thyme and bay leaves. Return the sausages to the pot.
Bring the mixture to a simmer. Cover the pot and cook for 30 minutes, or until the vegetables are tender.
Season with salt and black pepper. Remove the bay leaves before serving. Sprinkle with chopped parsley.