French Onion Scalloped Potatoes

5 from 2 votes

Creamy, cheesy scalloped potato casserole topped with crispy French onions.

Prep Time10

Cook Time30

Total Time40

Course: Side Dish

Cuisine: American

Servings: servings

1 ½ pounds gold potatoes or baby Yukon potatoes, washed and thinly sliced (⅛ of an inch thick)
2 tablespoons butter
3 tablespoons flour
2 teaspoons garlic powder
2 cups milk
1 ½ cups shredded white sharp cheddar cheese divided (may sub an Italian cheese blend for milder flavor)
½ packet ranch seasoning/dressing mix (If you love ranch flavor, you can use the whole packet)
salt and pepper to taste (I used about 1 teaspoon salt, ½ teaspoon pepper)
optional: ½ red onion thinly sliced
1 cup crispy French onions (usually found with the salad toppings and croutons)

Preheat oven to 375. Place sliced potatoes in a large pot and cover with water. Bring to a boil over medium high heat. Cover and cook about 15-minutes or until potatoes are tender. (The thicker your potato slices are, the longer they will take to cook) Drain and set aside.
While potatoes are boiling, prepare the sauce. In a large sauce pan melt butter over medium heat. Add flour and stir until mixture clumps up. Slowly whisk in the milk until a thick sauce forms. Add garlic powder, 1 cup of cheese, ranch seasoning, salt, and pepper and stir until cheese is melted and completely incorporated.
Add the sauce and potatoes to a large bowl and toss to coat. Transfer to a casserole dish. (If using red onions, layer them in with the potatoes) Sprinkle with remaining cheese. Bake, uncovered, for about 10 minutes until cheese is bubbly. Top with French onions and serve.

Make ahead by prepping, wrapping tightly and storing in fridge up to 24 hours. Transfer to preheated oven and add an extra 15 minutes to baking time.