- 1 lb. lean ground beef
- 1 yellow onion, diced
- 12 oz. baby bella mushrooms, finely chopped
- ¼ tsp. Kosher salt
- ¼ tsp. fresh ground black pepper
- 1 Tbsp. finely chopped fresh rosemary
- 1 Tbsp. fresh thyme
- 3 cloves garlic, minced
- 3 Tbsp. all-purpose flour
- 1 and ½ cups whole milk
- 1 cup frozen corn
- 1 cup frozen peas
- 2 cups shredded white cheddar
- 1 lb. tater tots (about 50-60)
- Preheat the oven to 425ºF. Heat a medium (10-inch), oven-safe skillet over medium-high heat. Line a plate with paper towel and set aside. Place the ground beef in the skillet and brown, breaking apart the beef into bite-sized pieces with a wooden spoon as it cooks. Cook for 5 to 7 minutes, until the beef is cooked through. Using a slotted spoon, transfer to the paper towel-lined plate to drain any excess grease off of the beef. Set aside.
- Add the onion and mushrooms to the skillet and season with the salt and ground pepper. Stir to coat the onions and mushrooms in the residual grease in the skillet. Cook, stirring occasionally, for 5 to 7 minutes, until the onions are translucent and the mushrooms appear juicy. Add in the rosemary, thyme and garlic. Stir to combine. Cook for another 1 to 2 minutes, until the garlic is golden and the herbs are fragrant. Add the browned beef back into the skillet, stirring to combine.
- Sprinkle the flour over the beef, onions and mushrooms, stirring to combine. Cook for 2 minutes, until the flour smells toasty and is no longer white. While stirring, slowly add in the milk. The milk will bubble violently at first, so take care to use your wooden spoon to scrape the brown bits up off of the bottom of the skillet as you add the milk – this is where the flavor is! Reduce the heat to low and cook, stirring occasionally, for 5 minutes, until the sauce is thickened and creamy. Add the corn and peas, stirring to combine. Taste and season with additional salt and pepper as desired.
- Turn the heat under the skillet off and top the beef and mushroom sauce with the shredded cheddar. Add the tater tots, one at a time, arranging them in a single layer that covers the top of the casserole completely.
- Bake the tater tot casserole for 30 minutes, until the tater tots are golden brown. Cool for a few minutes before serving.