Begin by peeling and dicing the potatoes. Chop the onion and mince the garlic. Set aside.

In a large pot, heat the olive oil over medium heat. Add the chopped onion and sauté until translucent, about 3-4 minutes. Stir in the minced garlic and cook for an additional minute until fragrant.

Add the diced potatoes to the pot and pour in the vegetable broth. Bring it to a boil, then reduce the heat to a simmer. Allow it to cook for about 15-20 minutes or until the potatoes are tender.

Once the potatoes are soft, stir in the Cajun seasoning, and season with salt and pepper to taste. Mix well so the flavors meld together.

Carefully mash some of the potatoes in the soup for a creamier texture. Stir in the cream or milk, and allow the soup to simmer for an additional 5 minutes.

Ladle the soup into bowls and garnish with chopped green onions. Serve hot and enjoy!