Preheat your oven to 350°F. While it heats, peel and slice the potatoes into 1/4-inch rounds—I like to use a mandoline for uniform slices that cook evenly. Set the sliced potatoes aside in a bowl (you can toss them with a little water to prevent browning if prepping ahead). Measure out all your seasonings (salt, black pepper, onion powder, and garlic powder) into a small bowl, and shred your cheddar cheese if not already shredded.

Heat a large skillet over medium-high heat and add the ground beef. Break it into crumbles as it cooks, stirring occasionally, until it's completely browned and cooked through (about 8-10 minutes). Drain off excess fat using a colander or by tilting the pan and pressing the meat with a spoon. For better flavor depth, I like to let the meat sit undisturbed for the first minute or two in a hot pan—this develops a nice browning rather than just steaming it.

In a large mixing bowl, combine the two cans of gluten-free cream of mushroom soup and the milk, stirring until smooth and well combined. Add the seasonings from Step 1 (salt, black pepper, onion powder, and garlic powder) and stir until the sauce is evenly flavored. Set aside.

Grease a 9x13-inch baking dish with butter or cooking spray. Begin layering: spread half of the sliced potatoes from Step 1 as the first layer on the bottom of the dish. Top with half of the cooked ground beef from Step 2, then pour half of the creamy sauce from Step 3 over the beef. Sprinkle half of the shredded cheddar cheese on top. Repeat the layers with the remaining potatoes, beef, sauce, and cheese, finishing with cheese on top.

Cover the casserole tightly with aluminum foil and place it in the preheated 350°F oven. Bake for 1 hour covered—this allows the potatoes to soften in the moist environment. After 1 hour, carefully remove the foil and bake uncovered for an additional 30 minutes. This final phase lets the top layer of cheese brown and the potatoes near the top develop a slightly firmer texture.

Remove the casserole from the oven and let it rest for 10 minutes before serving. This resting period allows the dish to set slightly and makes it easier to portion without everything falling apart. The potatoes will continue to soften gently during this time, and the flavors will meld together beautifully.