Cover the muffin tin loosely with foil (tent it so it doesn’t press on the cheese) and bake in the preheated oven for 25 minutes to help the potatoes soften through without over-browning the tops too quickly.
Remove the foil and continue baking for another 20–25 minutes, or until the potatoes are tender when pierced with a knife and the tops are deeply golden brown with crispy, frilly edges and melted, bubbly cheddar overflowing slightly from the cups.
Let the potato stacks rest in the muffin tin for about 5–10 minutes after baking. This short rest helps them hold together so you can lift them out in neat stacks. Run a small knife around the edges of each cup to loosen, then gently lift each stack out with a fork or spatula, keeping the crispy cheese attached.
Serve the sharp cheddar potato stacks warm, straight from the muffin tin or transferred to a serving platter, making sure everyone gets some of the browned, cheesy bits that collect around the edges.
For picky eaters or kids who like things a little milder, swap part of the sharp cheddar for a milder cheddar or Colby Jack so the flavor isn’t quite as bold. If you need to keep it very simple, you can reduce the salt slightly and let everyone add a bit at the table. For a slightly different texture, try Yukon Gold potatoes for a creamier center, or russets for extra crisp edges. You can also adjust the size: fill the cups only halfway for smaller stacks that are easier for little hands, or really mound them up for dramatic, overflowing stacks when entertaining. If your family likes more browned cheese, add an extra sprinkle of cheddar to just the tops in the last 5 minutes of baking. These reheat nicely in a hot oven or air fryer, so you can make them earlier in the day and crisp them back up right before dinner.