Preheat oven to 375ºF (190ºC). Spray a 9X13 inch baking dish with nonstick cooking spray; set aside.
In a large pot, cook the ground beef (1 pound), salt (1/2 teaspoon), black pepper (1/2 teaspoon), and onion (1/2 cup) over medium heat, crumbling the beef as it cooks, until there is no pink left in the beef, and the onions have softened, about 10 minutes.
Add minced garlic (4 cloves) and cook, stirring frequently, until fragrant, about 1 minute. Remove and discard excess grease from the pan.
Stir in Italian seasoning (2 teaspoons), Worcestershire sauce (1 tablespoon), cream of mushroom soup (2 cans), beef broth (2 cups), and rice (1 cup). Stir until combined. Over high heat, bring mixture to a boil, then immediately reduce heat and simmer, covered, until rice is tender, about 25-35 minutes. **If at this time the rice isn't the texture you like, add broth or water, 1/4 cup at a time, as need. (May not be needed).
Remove pan from heat and let sit about 10 minutes. Stir in mixed vegetables (12 ounces) and sour cream (1/2 cup).
Transfer to the prepared baking dish. Sprinkle top with both cheeses and bake, uncovered, for 20-25, or until heated through and cheese is melted
Sprinkle with chopped parsley (2 tablespoons). Serve.
Notes
Taste For Seasoning: Make sure to sample the rice and beef mixture while cooking on the stove, and before placing it in the oven. Once the rice is just cooked, it is ready for assembly and baking. Time will vary depending upon heat and type of pan.
Thawing: Make sure the veggies are thawed so the temperature of the beef mixture is not affected too much. The temperature of the mixture will determine the cooking time.
Baking Dish: Use a 9x13 baking dish and spray it with nonstick cooking spray. Clean-up will be quick and easy.
Oven Rack: Place the dish in the middle rack of the oven. This will ensure even cookin