There is a reason classic recipes stick around and continue to be made year after year. These recipes are simple, delicious, and don’t need reinventing! Potatoes au gratin are similar to scalloped potatoes, but with a cheese topping or sometimes even a buttery bread crumb topping. Both are delicious and require potatoes being cooked in a decadent creamy sauce. Let’s be honest though: if you are like me, you probably put cheese on all of your potatoes no matter what the recipes says! I am going to show you the basics on making potatoes au gratin that will be the perfect addition to your Sunday supper.
2 pounds of Russet potatoes, washed well (about 4 large russet potatoes)
1 large sweet onion
2 cups of milk (2% or whole)
2 cups of shredded cheddar cheese (Can use any variety of cheese)
3 tablespoon all purpose flour
3 tablespoon butter
1 tablespoon salt
1/2 tablespoon cracked black pepper
3 green onions (optional)
9 x 12 rectangular baking dish or a 12″ circular baking dish
Step 1: Preheat oven to 400 degrees.
Step 2: Slice Potatoes and Onion
Prior to slicing, peel the potatoes if you desire. I happen to love the look and taste of leaving the skin on. Next, slice the potatoes very thin along with slicing the onion into thin rings. Set aside.
Step 3: Layer Potatoes and Onion into a Baking Dish
Spray the baking dish with non-stick spray and then layer the first layer of potatoes in the bottom of the dish. Next, layer the onion slices over top of the potatoes, and repeat until the baking dish is full.
Step 4: Heat Flour and Butter in a Large Saucepan
Heat a large saucepan over medium heat. Add flour and butter and whisk for 2 to 3 minutes until flour has cooked slightly.
Step 5: Add Milk to Create the Cream Sauce
Whisk in milk to the butter and flour, and continue to stir until liquid coats the back of the spoon letting you know it is the right consistency. Season the cream sauce with salt and pepper.
Step 7: Pour the Cheesy Cream Sauce Over the Layered Potatoes
Once the cheese has melted, pour the cheese sauce over the layered potatoes letting it coat all of the potatoes. Top the casserole with the remaining shredded cheese.
Step 8: Cover the Dish and Bake for 1 1/2 Hours
Cover the potatoes au gratin with aluminum foil and bake for 1 1/2 hours until the potatoes are tender. For the last 15 minutes of cook time, remove the aluminum foil and let the cheese brown on top. Let the casserole sit for 15 minutes and top with chopped green onions if desired.