Brown the Beef: In a Dutch oven or large soup pot, brown the ground beef. Season with a pinch of salt and pepper while cooking. Once browned, remove the beef and set it aside.
Sauté Vegetables: In the same pot, melt 1 tbsp butter. Add the onion, celery, and carrots. Cook over medium heat for 8–10 minutes until softened. Stir in the dried parsley and basil.
Simmer: Add the cooked ground beef back into the pot, followed by the potatoes and chicken broth. Cover and cook on medium-low to medium heat for 10–13 minutes, or until potatoes are tender. Note: You may want to add the ¾ tsp salt and ½ tsp pepper at this stage to help the potatoes absorb more flavor.
Make the Thickener (Roux): While the soup simmers, melt 4 tbsp butter in a separate skillet over low to medium-low heat. Sprinkle in the flour and stir; cook for 4–5 minutes until it is a golden color.
Thicken the Soup: Add the butter and flour mixture directly to the soup and stir. Let it cook for about 2 minutes.
Add Dairy: Turn the heat down to low. Stir in the milk, salt, and pepper (if you haven't added them already).
Finish: Stir in the cheddar cheese until melted. Finally, stir in the sour cream.
Serve: Top with crumbled bacon if desired.