Begin by peeling and dicing your potatoes into bite-sized pieces. Then, boil them in a pot of salted water until fork-tender, which should take about 15-20 minutes. Drain and set aside.

In a large pot, mix the chicken stock, diced onion, salt, pepper, and 1 cup of cold water. Simmer over medium heat for about 20 minutes, allowing those flavors to meld together beautifully.

In a separate saucepan, melt the butter over low heat. Gradually whisk in the flour, stirring continuously until it forms a smooth roux. Cook this mixture for 1-2 minutes; it should bubble gently but not brown.

Slowly whisk the roux into the simmering broth mixture, mixing well to ensure there are no lumps.

Stir in the heavy whipping cream and let it simmer for an additional 20 minutes, stirring occasionally.

Gently fold the cooked, drained potatoes into the soup and stir well until everything is evenly combined.

Ladle your delicious soup into bowls and top each serving with a generous amount of shredded cheddar cheese and diced green onions.