Heat 1 Tablespoon olive oil over a medium-high heat. Add 1 onion, finely diced and cook, stirring, for around 3 minutes or until softened. Add 3 garlic cloves, minced and cook, stirring, for 1 minute or until fragrant.
Add 1 pound ground beef, cook and crumble, until the beef is cooked and no longer pink.
Add 2 Tablespoons tomato paste and 2 Tablespoons all purpose flour and cook, stirring for 1 minute. Gradually add2 cups beef broth while stirring until well combined.
Add 2 cups frozen mixed vegetables along with 1 Tablespoon Worcestershire sauce and 1 teaspoon dried thyme. Cook, stirring occasionally, until the vegetables have heated through. Season to taste with salt and pepper. Remove from the heat.
Transfer the mixture to a 9x13-inch baking dish. Arrange the 2 pound bag frozen tater tots in a single layer over the meat mixture. Sprinkle 1 1/2 cups shredded cheddar cheese evenly over the tater tots.
Bake uncovered for about 30 minutes on the middle rack, or until the tater tots are cooked through and golden in color.
Garnish the casserole with 1/4 cup finely chopped fresh parsley, if using, before serving.
Notes
Please refer to my FAQ’s (Frequently Asked Questions) and ingredient list above for other substitutions or for the answers to the most common questions.
I like this casserole with a decent amount of "gravy" with the casserole mixture, if you prefer a thicker mixture, you can use a cornstarch slurry. Just combine 1 Tablespoon of cornstarch with 2 Tablespoon of water, and add it to the skillet. Turn the heat up to high and stir the mixture until it has thickend appropriately.