In a large stock pot, brown the ground beef over medium heat until cooked through. Drain the fat, stir in the seasoning salt to coat the beef, and set the beef aside.
Add 1 tablespoon of butter to the bottom of the stock pot set over medium heat. Once melted, add the onions and cook for 5 minutes or until translucent.
Stir in the garlic and parsley and cook 1 more minute.
Add the corn, potatoes, cooked ground beef, and chicken stock to the pan.
Bring to a boil, reduce heat to medium-low, and cover. Cook for 10-15 minutes or until the potatoes are tender.
In a small saucepan, melt the remaining 4 tablespoons of butter.
Whisk in the flour and cook for 2 minutes, whisking constantly.
Whisk in the milk and cook until thickened to consistency of a thin gravy.
Add the flour mixture to the pot of soup, along with the cheddar.
Stir to combine and continue cooking over medium-low heat until the cheese has melted and the soup has thickened, stirring occasionally.
Serve with croutons, diced tomatoes, and green onions, as desired.