Crispy Topped Beef & Vegetable Casserole

1. Preheat Oven

Adjust your oven rack to the upper-middle position and preheat the oven to 450°F.

2. Cook Beef Mixture

In a Dutch oven, combine the ground beef, sliced mushrooms, chopped onion, minced garlic, fresh thyme, salt, and black pepper. Cook over medium heat for 25 to 28 minutes, stirring occasionally, until nearly all the liquid has evaporated and the mixture looks mostly dry.

3. Thicken Mixture

Stir in the all-purpose flour and cook for about 1 minute. Gradually add the whole milk and chicken broth, stirring and scraping up any browned bits from the bottom of the pot. Bring the mixture to a simmer and cook until it thickens, about 3 minutes.

4. Add Cheese

Remove the pot from heat and stir in the grated Parmesan cheese until fully incorporated.

5. Prepare Baking Dish

Transfer the beef mixture to a 13 by 9-inch baking dish, spreading it out evenly. Sprinkle the frozen peas and corn evenly over the beef mixture.

6. Add Tater Tots

Arrange the frozen tater tots in a single, even layer on top. Do not press them down; simply place them lightly.

7. Bake Casserole

Bake the casserole in the preheated oven for 35 to 38 minutes, rotating the dish halfway through to ensure even browning. The tater tots should be deep golden brown and the filling should be bubbling around the edges.

8. Cool and Serve

Let the casserole cool for about 15 minutes before serving. This allows the flavors to meld and the filling to set, making it easier to serve.