1. Start by placing the diced potatoes in a large pot, covering them with water, and adding 3/4 teaspoon of salt. Bring the pot to a boil and cook the potatoes until they’re tender, about 15 minutes. Drain the potatoes and mash them together with the sour cream and 1 tablespoon of butter. Set the mashed potatoes aside.

2. In a large soup pot, cook the ground beef over medium heat until it’s nicely browned. Drain any excess grease, then remove the beef from the pot and set it aside.

3. In the same pot, melt 2 tablespoon of butter. Add the diced onion and cook until softened, about 5 minutes. Stir in the minced garlic and cook for another minute.

4. Sprinkle the flour over the onion mixture and stir for 1-2 minutes. Slowly whisk in the chicken broth until the mixture is smooth and free of any lumps.

5. Stir in the half and half, Worcestershire sauce, Italian seasoning, mustard powder, and ground sage. Bring the soup to a simmer.

6. Return the browned beef to the pot, then stir in the mixed vegetables and shredded cheddar cheese. Let the soup simmer for about 10 minutes, allowing the flavors to meld and the cheese to melt.

7. Finally, stir the mashed potatoes into the soup, incorporating them until the soup is creamy and the potatoes are fully combined.

8. Adjust the seasoning with salt and pepper to taste. Ladle the Shepherd’s Pie Soup into bowls and serve it hot, with a side of crusty bread for dipping.