Heat the vegetable oil in a large pot over medium heat.
Add the chopped onion and garlic, and sauté until softened, about 5 minutes.
Add the diced potatoes and carrot to the pot.
Cook for a few minutes, stirring occasionally.
Pour in the chicken or vegetable broth.
Bring the mixture to a boil, then reduce heat to low.
Simmer until the potatoes and carrot are tender, about 20 minutes.
Use an immersion blender to puree the soup until smooth. (Alternatively, transfer the soup in batches to a blender, blend, and return it to the pot.)
Stir in the whole milk and heavy cream.
Add the grated cheese and ground cumin.
Season with salt and pepper to taste.
Simmer the soup for an additional 5 minutes, allowing the flavors to meld together.
Ladle the soup into bowls.
Garnish with chopped fresh cilantro and avocado slices.
Enjoy your meal!