Cheesy loaded baked potato au gratin topped with crispy bacon, melted cheddar, and sliced green onions in a golden, bubbling casserole dish.

Loaded Baked Potato Au Gratin with Ranch, Bacon & Green Onions

This Loaded Baked Potato Au Gratin takes all the best parts of a classic loaded baked potato—creamy ranch seasoning, crispy bacon, melty cheddar cheese, and fresh green onions—and layers them into a rich, bubbling au gratin casserole. Thinly sliced potatoes are baked in a silky ranch-infused cheese sauce, then topped with plenty of bacon and extra cheese for the ultimate comfort food side dish. Perfect for holidays, family dinners, potlucks, or anytime you want a hearty, crowd-pleasing potato dish with big flavor and a fully loaded finish.

Course Casserole, Comfort Food, Holiday Side, Side Dish

Cuisine American, Comfort Food Cuisine, Southern-Inspired

Keyword bacon potato gratin, cheesy potato casserole, creamy cheesy potatoes, easy potato side dish, green onion potato casserole, holidays potato recipe, loaded baked potato au gratin, loaded potato casserole recipe, ranch bacon potato au gratin, ranch potato bake

Prep Time 20

Cook Time 1 10

Total Time 1 30

Servings 8

Ingredients

3 lbs Yukon Gold or Russet potatoes, thinly sliced (⅛ inch)
6 slices thick-cut bacon, cooked and crumbled
2-3 green onions, sliced
2 cups shredded cheddar cheese (sharp works best)
1 cup shredded Monterey Jack or mozzarella
2 tbsp unsalted butter
2 tbsp all-purpose flour
1½ cups heavy cream
1 cup whole milk
1 packet ranch seasoning mix (1 oz)
½ tsp garlic powder
½ tsp onion powder
½ tsp black pepper
salt, to taste
Optional: extra cooked bacon + green onions for topping

Instructions

Prep the Oven & Dish

Preheat oven to 375°F (190°C).
Grease a 9×13-inch baking dish or large casserole dish.

Make the Ranch Cheese Sauce

In a medium saucepan over medium heat, melt the butter.
Whisk in the flour and cook for 1 minute to form a roux.
Slowly pour in the heavy cream and milk, whisking constantly until smooth.
Add:
ranch seasoning
garlic powder
onion powder
black pepper
Simmer 2–3 minutes until slightly thickened.
Remove from heat and stir in 1 cup cheddar and ½ cup Monterey Jack, mixing until melted.

Assemble the Au Gratin

Layer like this:
First layer
A thin layer of sliced potatoes
Spoonfuls of ranch cheese sauce
Sprinkle of bacon
Sprinkle of green onions
Sprinkle of cheddar + Monterey Jack
Repeat layers until all ingredients are used.
End with a generous amount of cheese on top.

Bake

Cover with foil and bake 45 minutes.
Remove foil and bake 20–25 more minutes, until golden, bubbly, and potatoes are very tender.