Easy Potatoes Au Gratin
Tender sliced potatoes baked to perfect with a creamy sauce made with milk, cheese, garlic, mustard, and onions.
Prep Time15 minutes mins
Cook Time1 hour hr 20 minutes mins
Total Time1 hour hr 35 minutes mins
Course: Side Dish
Cuisine: American, French
Servings: 8
- 2 lb potatoes peeled and thinly sliced
- Kosher salt and freshly ground black pepper to taste
- 3 tbsp olive oil divided
- 1 medium yellow onion thinly sliced
- 3 garlic cloves minced
- 1 tbsp wholegrain mustard
- 3 tbsp gluten-free flour or cornstarch
- 2 1/2 cups almond milk
- 1 tsp freshly grated nutmeg or to your taste
- ¾ cup grated Gruyère cheese
- Fresh thyme to garnish
Preheat the oven to 350F and spray a baking dish with cooking oil spray or olive oil.
Add sliced potatoes and season with salt and pepper. Drizzle 2 tbsp oil and toss well to coat. Place in the preheated oven and bake for 15 minutes, or until potatoes begin to soften and the sauce is ready.
Meanwhile, heat a rimmed pan over medium heat and drizzle with 1 tbsp oil. Sauté the onion and garlic for 2-3 minutes, or until it softens.
Stir in the mustard and flour. Slowly pour the milk and whisk until sauce is thickened and smooth, 2-3 minutes.
Season with salt, pepper, and nutmeg.
Remove the potatoes from the oven and pour over the sauce, stirring gently to mostly cover and coat.
Top with shredded cheese. (You can now cool and refrigerate the dish for make-ahead.)
Return to the oven and bake for 60 minutes, or until potatoes are super tender, bubbly, and golden-brown on top. (Cooking time may vary depending on the size of the thickness of your potato slices.)
Garnish with fresh thyme before serving.
Oven temperature: Please note that everyone's will be different and cook time will vary. If you try a higher temperature of 400F it will take 35-40 minutes. At 350F it will need 50-60 minutes depending.
Milk: we used almond milk, but you may use any other milk of choice.
Mustard: whole grain mustard was used but you may use dijon mustard
Cheese: If you don't like gruyere or want to use another cheese, consider using a mix of sharp cheddar and parmesan, or gouda.
Potatoes: consider using Yukon gold potatoes
Flour: Any flour would work for this recipe. Feel free to use cornstarch too. We love to use Whole wheat as well.
Bake time: Don't rush them, they need a good one hour in the oven depending on your oven
Calories: 127kcal | Carbohydrates: 4g | Protein: 5g | Fat: 10g | Saturated Fat: 3g | Cholesterol: 14mg | Sodium: 165mg | Potassium: 35mg | Fiber: 1g | Sugar: 1g | Vitamin A: 117IU | Vitamin C: 1mg | Calcium: 226mg | Iron: 1mg