Combine the frozen hash browns, diced onion, garlic powder, black pepper, salt, and dried thyme in a large pot.

Pour in enough water or broth to cover the ingredients, about 4-6 cups, and bring to a boil over medium-high heat.

Reduce heat to low and let the soup simmer uncovered for about 30-35 minutes, stirring occasionally.

Once the hash browns are tender, turn off the heat and stir in the heavy cream until fully incorporated.

If desired, add the shredded cheese and stir until melted completely.

Ladle the soup into bowls and serve immediately, garnished with cheese or herbs if desired.