01 -
In a large bowl, combine ground beef, breadcrumbs, egg, milk, onion, garlic powder, Worcestershire sauce, salt, and pepper. Mix well until evenly combined.
02 -
Roll the mixture into 1-inch meatballs.
03 -
Heat olive oil in a large skillet over medium heat. Fry the meatballs in batches, turning them to brown all sides. Cook for about 7-8 minutes or until fully cooked through. Set aside.
04 -
In the same skillet, melt butter over medium heat. Add the sliced onions and cook until soft and golden brown, about 5 minutes.
05 -
Stir in the flour and cook for 1 minute to remove the raw flour taste. Gradually whisk in the beef broth, Worcestershire sauce, and Dijon mustard. Add thyme (if using) and season with salt and pepper. Simmer the gravy until it thickens, about 5-7 minutes.
06 -
Return the meatballs to the skillet, coating them in the gravy. Simmer for another 5 minutes to heat through.
07 -
Boil the peeled and cubed potatoes in salted water until tender, about 15-20 minutes.
08 -
Drain the potatoes and return them to the pot. Add butter, milk, sour cream (if using), salt, and pepper. Mash the potatoes until smooth and creamy.
09 -
Spoon the mashed potatoes onto plates and top with the Salisbury meatballs and gravy. Garnish with parsley if desired and serve immediately.