Easy Cheesy Potato and Onion Au Gratin is deliciously creamy and a real show stopper. It’s a simple side dish that takes minutes to put together, but is packed with cheesy goodness. What’s even better is that it can be made ahead of time, and leftovers, if any are just as good the next day. Who could ask for more?
Ingredients for Easy Cheesy Potato and Onion Au Gratin:
I used the following ingredients for this outrageously delicious dish: Onions, unsalted butter, all-purpose flour, milk, salt, freshly ground black pepper, extra sharp Cheddar cheese, russet potatoes, and dry breadcrumbs.
Before putting the dish together, I sautéed thinly sliced onions in some melted butter over medium heat for about 10 minutes. After 10 minutes, the onions were nicely tender.
Making the Easy Cheesy Potato and Onion Au Gratin Cheese Sauce:
While the onions were sautéing, I made the cheese sauce. I started by melting some butter in a saucepan over medium heat. Once the butter was melted, I whisked in flour, and let it cook for about a minute. Then, I added the milk, salt, and pepper, and continued to whisk until the sauce had thickened. Finally, I added the shredded cheese, and whisked the sauce until the cheese had melted and the sauce was smooth.
Putting the Easy Cheesy Potato and Onion Au Gratin Together:
Once the onions and cheese sauce were ready, it was time to build the casserole. First, I layered half of the thinly sliced potatoes in a 2-quart baking dish that I had sprayed with vegetable spray. Then, I topped the potatoes with the sautéed onions, and poured on half of the cheese sauce. I followed that with the remainder of the potatoes and cheese sauce.
I covered the casserole, and popped it into a preheated 400° F oven for 1 hour and 15 minutes. After that, I removed the top and added some additional shredded cheese. Then, I sprinkled on some breadcrumbs, and dotted the top with some butter. I returned the potatoes and onions to the oven for an additional 30 minutes.
The Easy Cheesy Potato and Onion Au Gratin was incredible. It was full of creamy and cheesy goodness, with just a hint of onion. I served it with the Master Taste Tester’s meatloaf and some mushy peas. Yum!
Easy Cheesy Potato and Onion Au Gratin
- 1 onion thinly sliced (about 2 cups)*
- 5 Tablespoons butter divided
- 3 Tablespoons all-purpose flour
- 1 teaspoon salt
- ¼ teaspoon freshly ground black pepper
- 2 cups milk
- 2 cups (8 ounces) shredded Cheddar cheese, divided
- 2 pounds russet potatoes thinly sliced (about 5 cups)*
- 3 Tablespoons dry breadcrumbs
- Preheat oven to 400° F. Butter or spray with vegetable spray a 2-quart casserole dish.
- Sauté onions in 1 tablespoon of melted butter over medium heat until softened, about 10 minutes. Set aside.
- In a medium-size saucepan, melt butter over medium heat. Whisk in the flour. Stir constantly with a whisk for one minute. Add milk; whisk until mixture has thickened. Stir in 1 ½ cups of cheese; continue whisking until melted, about 30 to 60 seconds.
- Layer ½ of the potatoes into bottom of the prepared casserole dish. Top with the sautéed onions and ½ of cheese sauce. Top with the remaining potatoes and remaining cheese sauce.
- Cover dish and cook 1 hour and 15 minutes in the preheated oven. Remove cover; top with remaining ½ cup of cheese and breadcrumbs. Dot with remaining butter. Return to oven and continue cooking for 15 minutes, or until cheese is melted and potatoes are tender.
- Yield: 6 servings.