Step 1

Preheat the oven to 375 degrees.

Step 2

Heat the oil or butter in a large stove-top casserole dish or large oven-safe skillet to medium. Add the onion and sauté 4-5 minutes or until soft. Add the ground beef and cook another 5-7 minutes or until browned, breaking up the pieces with a wooden spoon as it cooks. Stir in the mixed vegetables and sauté another 2-3 minutes. Stir in the salt, mustard powder, celery salt, onion powder, garlic powder and black pepper.

Step 3

Stir in the flour until incorporated. Increase the heat to medium-high. Add the stock and bring to a simmer, stirring constantly for 2-3 minutes, until thickened. Taste and adjust the seasoning, if necessary. Stir in the Worcestershire sauce (if using). Remove from the heat and flatten the beef mixture in an even layer.

Step 4

Sprinkle the cheddar cheese in an even layer over the beef mixture. Line with tater tots. Bake 20-25 minutes or until the tater tots are golden and crispy and the filling is bubbly. Let rest for 5 minutes, then scoop and serve.