A delightful twist on classic au gratin potatoes, featuring a creamy cheese sauce and tender Yukon gold potatoes.
Preheat your oven to 375°F and lightly grease a 2-quart baking dish with cooking spray.
Ensure the baking dish is evenly coated to prevent sticking.
Melt the butter in a large pot over medium heat. Add the chopped onion and sauté until softened and slightly golden.
Stir frequently to avoid burning the onions.
Sprinkle the flour over the onions and stir well. Gradually pour in the milk while whisking to create a smooth sauce.
Whisk continuously to prevent lumps from forming.
Add the sliced potatoes to the sauce, stirring to coat them evenly. Bring the mixture to a gentle boil.
Ensure all potato slices are well coated with the sauce.
Stir in 1 cup of the cheese, salt, and pepper, mixing until the cheese is melted and incorporated.
Taste the sauce and adjust seasoning if necessary.
Transfer the mixture to the prepared baking dish, spreading it out evenly. Bake uncovered for 1 hour.
Check the potatoes for doneness by piercing with a fork.
Sprinkle the remaining cheese over the top and broil for 1-2 minutes until golden and bubbly.
Keep a close eye while broiling to avoid burning.
Let the dish cool for 5 minutes before serving. Slice into portions and enjoy!
Cooling helps the sauce set, making it easier to serve.
