My grandmother brought this 4-ingredient dish to our cookout and it disappeared in seconds.

If your family prefers a milder flavor, you can use half Swiss cheese and half a mild white cheese like mozzarella or Monterey Jack, keeping the total amount the same so the texture stays rich and stretchy. For kids who are picky about strong cheese, start with 3 cups Swiss and 1 cup mild cheese and see how they like it.

If you need to stretch the recipe for a bigger crowd, you can add up to 4 more ounces of noodles and an extra 1/2 to 1 cup milk, but be sure your slow cooker is large enough and stir a couple of times so the noodles cook evenly. For a slightly lighter version, you can use 2% milk, though the sauce will be a bit less rich and creamy; avoid using skim milk, as it tends to make the sauce thin and grainy.

To add a little texture for adults, top individual bowls with a sprinkle of black pepper or a spoonful of buttered breadcrumbs, keeping the base recipe at four ingredients so it stays true to its simple roots.

Food safety tips: Keep the slow cooker on LOW or WARM once the dish is done; don’t let it sit at room temperature for more than 2 hours. Cool leftovers quickly, transfer them to an airtight container, and refrigerate within 2 hours of cooking. Reheat leftovers thoroughly until steaming hot, adding a splash of milk to loosen the sauce if needed, and only reheat what you’ll eat—avoid reheating the same portion multiple times.