Preheat your oven to 400°F. Set a large, deep oven-safe skillet or a heavy Dutch oven over medium-high heat, drop in the lean ground beef and chopped yellow onion, and cook for 6 to 8 minutes while breaking the meat apart into uniform crumbles until the beef is fully browned and the onions turn soft.

Tilt the pan slightly to ladle out or drain away any heavy excess pooling grease, leaving just a thin coat of flavorful fats to gloss the beef, then reduce the stove heat to medium. Add the minced garlic straight to the hot meat and sauté for exactly 60 seconds until fragrant, making sure the garlic pieces do not scorch.

Pour the condensed cream of mushroom soup, condensed cream of chicken soup, and Worcestershire sauce directly into the skillet, stirring firmly to scrape up any savory browned bits stuck to the bottom of the pan until the meat is entirely enveloped in a smooth, thick, and simmering gravy matrix. Season the mixture generously with salt and black pepper to taste.

Stir the frozen sweet corn kernels, frozen peas, and exactly 1 cup of your freshly shredded sharp cheddar cheese directly into the hot, bubbling meat gravy until the cheese completely melts and strings throughout the filling.

Remove the skillet from the heat source and use a spatula to smooth the beef and vegetable filling into a flat, level surface. Arrange the frozen tater tots in tight, concentric circles or neat rows completely across the top of the hot beef mixture, pressing them down just slightly so they anchor into the gravy baseline.

Transfer the entire oven-safe skillet directly onto the middle rack of your preheated oven and bake uncovered at 400°F for 20 to 25 minutes. Watch closely until the potato crowns turn a deep, shatter-crisp golden brown and the cream sauce is bubbling violently along the perimeter edges of the pan.

Carefully slide the hot pan out, blanket the golden potato layer uniformly with the remaining 1 cup of shredded cheddar cheese, and return to the oven for an additional 5 minutes until the cheese is entirely liquefied and melted. Remove from the heat and let the casserole rest on the counter for 5 minutes so the rich dairy sauce can stabilize and tighten slightly before spooning into deep bowls.