Heat oil in a large skillet over medium heat. Add ground beef and cook until browned. Drain excess fat if needed.
2 Tablespoon vegetable oil, 2 pounds ground beef
Add the onion, tomato paste, garlic, rosemary, thyme, salt, pepper, Worcestershire, and beef stock to the crockpot. Stir to combine.
1 medium onion, 1/3 cup tomato paste, 1 teaspoon garlic, 1 teaspoon fresh rosemary, 1 teaspoon fresh thyme, 1 teaspoon salt, 1 teaspoon black pepper, 2 teaspoon worcestershire sauce, 2 cups beef stock
Add the cooked beef and sprinkle with flour. Stir until fully incorporated.
3 Tablespoon flour
The flour helps thicken the filling as it cooks.
Cover and cook on low for 3 hours.
Stir in the frozen vegetables. Spread the mashed potatoes evenly over the top.
12 ounces frozen mixed vegetables, 24 ounces refrigerated mashed potatoes
Mashed potatoes can be homemade or store-bought.
Cover and cook for another 30 minutes, until heated through.
Serve warm.
The flour helps thicken the filling as it cooks.