Bring a quart of water to a boil in a large pot. Add diced potatoes and cook until tender. Drain and set aside.

In a large pot, combine chicken stock, water, diced onions (if using), salt, and pepper. Simmer over medium heat for 20 minutes to let the flavors meld.

In a separate saucepan, melt the butter over medium heat. Whisk in the flour gradually to form a smooth roux. Let it cook for 2 minutes to remove the raw flour taste.

Slowly add the roux to the simmering broth, whisking continuously to avoid lumps. Cook until the mixture thickens.

Stir in the heavy cream and allow the soup to simmer for another 20 minutes, stirring occasionally.

Add the cooked potatoes to the soup and stir gently to combine.

Ladle the soup into serving bowls. Top with shredded cheddar cheese, crispy bacon bits, and chopped green onions for garnish.

Serve immediately and enjoy the creamy, indulgent flavors.