In a large pot over medium-high heat, brown 1 pound of lean ground beef until fully cooked, about 5-7 minutes, then add 1 cup of diced yellow onions and stir frequently.

Reduce heat to medium and add in 1/2 cup of butter. Stir until melted, then sprinkle 1/2 cup of all-purpose flour over the mixture and cook the roux for about 3 minutes.

Gradually whisk in 3 cups of chicken broth to the roux, ensuring to scrape the bottom of the pot. Slowly add 3 cups of half-and-half cream, whisking to maintain a smooth consistency.

Sprinkle in 1 tablespoon of garlic powder, 1 tablespoon of onion powder, along with 1 teaspoon each of salt and pepper, stirring to evenly distribute the seasonings.

Add in 3 cups of frozen diced hash brown potatoes, stirring to combine. Let come to a gentle simmer for about 10 minutes, stirring occasionally.

Stir in 1 cup of chopped green onions and 2 cups of shredded triple cheddar cheese blend until fully melted, achieving a velvety consistency.