Step 1: Prepare the Mashed Potatoes

1. Bring a large pot of salted water to a boil. Add the cubed potatoes and cook until tender, about 15-20 minutes.
2. Drain the potatoes and return them to the pot.
3. Add milk, butter, salt, and pepper. Mash until smooth, adjusting the milk to achieve your desired consistency. Cover and set aside.

Step 2: Cook the Ground Beef

1. In a large skillet over medium heat, cook the ground beef until browned and fully cooked.
2. Remove the beef from the skillet and set aside. Drain excess fat, leaving about 1 tablespoon in the skillet.

Step 3: Make the Gravy

1. In the same skillet, sauté the chopped onion and garlic until softened, about 2-3 minutes.
2. Sprinkle the flour over the onion and garlic mixture, stirring to combine. Cook for 1 minute.
3. Slowly whisk in the beef broth, ensuring there are no lumps.
4. Stir in Worcestershire sauce, soy sauce, salt, pepper, and thyme (if using). Let the gravy simmer until thickened, about 5 minutes.
5. Add the cooked ground beef back into the skillet, stirring to coat in the gravy.

Step 4: Assemble and Serve

1. Spoon a generous portion of mashed potatoes onto a plate.
2. Top with the ground beef and gravy mixture.
3. Garnish with chopped parsley or chives, if desired.