Ingredients
Potatoes and Vegetables
- 4 pounds Russet potatoes (peeled and sliced to 1/8-inch thick)
- 1 large white or yellow onion (diced small)
- 3 to 4 cloves garlic (finely minced or pressed)
Cheese
- 1.5 cups shredded Colby Jack cheese (divided)
- 1.5 cups shredded cheddar cheese (divided)
- 1 cup shredded Parmesan cheese (divided)
Other Ingredients
- 2 tablespoons unsalted butter
- 2 tablespoons all-purpose flour
- 2 teaspoons Kosher salt (or to taste)
- 2 teaspoons seasoning blend such as Mrs. Dash, Trader Joe’s 21 Salute, or poultry seasoning
- 1 teaspoon freshly ground black pepper (or to taste)
- 1 cup vegetable or chicken broth
- 1 cup heavy cream
- 1 cup sour cream
Instructions
- Preheat and Prepare Potatoes: Preheat your oven to 400°F. Arrange the peeled and thinly sliced Russet potatoes upright in a 9×13-inch casserole dish along one of the long edges, creating three columns of potato slices across the dish. If available, use a mandoline slicer for even slices.
- Sauté Onion and Garlic: In a saucepan, melt the unsalted butter over medium heat. Add the diced onion and minced garlic; cook for about 5 minutes, stirring frequently until the onion is softened and fragrant.
- Make Roux: Sprinkle in the all-purpose flour and cook for an additional minute, whisking constantly, until the flour starts to turn a light golden brown. This roux will thicken your sauce.
- Add Seasonings and Liquids: Stir in the Kosher salt, seasoning blend, freshly ground black pepper, broth, and heavy cream. Continue stirring and cooking the mixture for about 3 minutes until it has thickened slightly.
- Add Cheese to Sauce: Remove the saucepan from heat and stir in 1 cup each of Colby Jack and cheddar cheeses, plus 1/2 cup of Parmesan cheese. Set the cheese sauce aside.
- Layer with Sour Cream and Sauce: Evenly spread the sour cream over the arranged potatoes in the casserole dish, then pour the cheesy sauce mixture evenly over the potatoes.
- Top with Remaining Cheese: Sprinkle the remaining 1/2 cup each of Colby Jack, cheddar, and Parmesan cheeses evenly over the potatoes and sauce.
- Bake Covered: Cover the casserole dish with foil and bake in the preheated oven for 1 hour. After this time, check the potatoes for doneness by testing if they are fork tender. If not fully cooked, cover again and bake for an additional 10 to 15 minutes as needed.
- Bake Uncovered to Brown: Once the potatoes are tender, remove the foil and continue baking uncovered for another 30 minutes or until the cheese topping is nicely browned. Keep a close eye to prevent burning during this stage.
- Cool and Serve: Remove the scalloped potatoes from the oven and let them cool for about 5 minutes before serving to allow the dish to set and flavors to meld.
Notes
- Using a mandoline slicer ensures uniform potato slices, which promotes even cooking.
- The seasoning blend can be varied to your taste; poultry seasoning or a salt-free mix like Mrs. Dash works well.
- To make this dish vegetarian, use vegetable broth instead of chicken broth.
- If you prefer a stronger cheese flavor, experiment with sharper cheddar or add an extra 1/4 cup of Parmesan.
- Covering the dish during initial baking helps steam the potatoes to tender perfection, while uncovering allows the cheese to brown beautifully.
- Letting the dish rest after baking makes it easier to serve and enhances the texture.
- Prep Time: 20 minutes
- Cook Time: 1 hour 30 minutes
- Category: Side Dish
- Method: Baking
- Cuisine: American
- Diet: Vegetarian
