Cheesy Au Gratin Potatoes
Ingredients
- 3 lbs Yukon gold potatoes, about 6–7 medium, sliced into ⅛-inch rounds
- ½ medium yellow onion, thinly sliced
- For the sauce:
- 2 tablespoons unsalted butter
- ¼ cup all-purpose flour
- 1 ½ cups whole milk
- 8 ounces sharp cheddar cheese, shredded (about 2 cups)
- ½ teaspoon onion powder
- ½ teaspoon dried rosemary, finely crushed
- ¾ teaspoon kosher salt, plus more to taste
- Freshly ground black pepper, to taste
- For topping:
- ½ cup shredded Gruyere cheese
- ¼ cup grated Parmesan cheese
- Freshly chopped parsley for garnish
Instructions
- Preheat oven to 375°F. Grease a 2-quart baking dish (8x12 works well) with butter or nonstick spray.
- Arrange potato slices in three slightly slanted rows, leaving space so they aren’t packed too tightly. Tuck onion slices between and on top of the potatoes.
- Make the sauce: In a medium saucepan over medium heat, melt the butter. Whisk in the flour and cook for 1 minute. Slowly whisk in the whole milk until smooth and thickened, about 3–4 minutes.
- Reduce heat to low and stir in cheddar cheese, onion powder, rosemary, salt, and pepper. Taste and adjust seasoning if needed.
- Pour the sauce evenly over the potatoes and onions. Cover tightly with foil and bake for 45 minutes.
- Remove foil, sprinkle Gruyere and Parmesan evenly over the top, then return to the oven for 30–40 minutes, or until the potatoes are fork-tender and the top is golden brown.
- Let rest 10 minutes before serving. Garnish with fresh parsley.
Serving: 0.5cup, Calories: 364kcal, Carbohydrates: 37g, Protein: 15g, Fat: 18g, Saturated Fat: 10g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 4g, Trans Fat: 0.1g, Cholesterol: 53mg, Sodium: 545mg, Potassium: 835mg, Fiber: 4g, Sugar: 4g, Vitamin A: 555IU, Vitamin C: 34mg, Calcium: 392mg, Iron: 2mg
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