Indulge in the ultimate comfort food with this Spuds and Onions Au Gratin recipe, a luxurious twist on classic scalloped potatoes. Layers of thinly sliced russet potatoes and sweet yellow onions are bathed in a velvety, herb-infused cheese sauce featuring Gruyère and Parmesan, then crowned with golden, crunchy panko breadcrumbs. A hint of garlic, freshly grated nutmeg, and aromatic thyme elevate this dish into a decadent side that’s perfect for family meals, holiday feasts, or anytime you want to impress your guests. With its creamy texture, bubbling cheese top, and irresistible crispy crust, this au gratin masterpiece is both delicious and visually stunning. Serve it alongside roasted meats or as a standalone vegetarian delight, and watch the compliments roll in!
Preheat your oven to 375°F (190°C) and grease a 9x13-inch baking dish with butter or nonstick spray.
Peel the potatoes and slice them thinly (about 1/8 inch thick). Use a mandoline slicer if available for even slices. Also, peel and thinly slice the onions.
In a medium saucepan, melt the butter over medium heat. Add the minced garlic and sauté for 30 seconds until fragrant.
Stir in the flour to create a roux. Cook for 1-2 minutes, stirring constantly, until the flour is a light golden color.
Gradually whisk in the milk and heavy cream, ensuring no lumps remain. Bring to a simmer, stirring frequently until the sauce thickens.
Reduce the heat to low and stir in Gruyère cheese, Parmesan cheese, salt, pepper, nutmeg, and thyme. Stir until the cheese melts and the sauce is smooth. Remove from heat.
Layer half of the potato slices evenly in the prepared baking dish. Spread half of the sliced onions over the potatoes.
Pour half of the cheese sauce over the first layer, using a spatula to spread it evenly.
Repeat the process with the remaining potatoes, onions, and cheese sauce, creating a second layer.
Sprinkle the panko breadcrumbs evenly over the top for a crispy golden crust.
Cover the dish with foil and bake in the preheated oven for 40 minutes.
Remove the foil and bake uncovered for another 20 minutes until the top is bubbling and golden brown.
Let the dish rest for 10 minutes before serving to allow the flavors to meld and the sauce to set.
Garnish with additional thyme leaves if desired and serve warm.
Calories |
3674 | ||
|---|---|---|---|
% Daily Value* |
|||
| Total Fat | 210.2 g | 269% | |
| Saturated Fat | 120.0 g | 600% | |
| Polyunsaturated Fat | 1.8 g | ||
| Cholesterol | 656 mg | 218% | |
| Sodium | 4850 mg | 211% | |
| Total Carbohydrate | 321.0 g | 117% | |
| Dietary Fiber | 25.4 g | 91% | |
| Total Sugars | 50.9 g | ||
| Protein | 120.5 g | 241% | |
| Vitamin D | 6.8 mcg | 34% | |
| Calcium | 3035 mg | 233% | |
| Iron | 16.1 mg | 89% | |
| Potassium | 7258 mg | 154% | |
*The % Daily Value tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.