Creamy Au Gratin Potatoes Recipe

These cheesy Au Gratin Potatoes are irresistibly creamy and full of flavor. If you love potatoes, this recipe is a must-try — perfect for family dinners or holiday feasts. Follow the step-by-step directions for reliably rich, tender, and cheesy potatoes every time.

My grandmother always made wonderful scalloped potatoes for Easter. After I married, my husband shared his family’s au gratin version — the main difference being the generous addition of cheese. Scalloped potatoes are layers of thinly sliced potatoes baked in a creamy sauce. Au gratin includes the same tender potatoes and creamy sauce but adds layers of gruyere and sharp cheddar, finished with a golden, melty cheese crust.

I’ve adapted that family scalloped recipe into what I consider the best au gratin potatoes by layering rich cheeses into the classic creamy base. These potatoes are a standout side for holidays like Thanksgiving and Christmas or any time you want an indulgent comfort dish. The finished casserole is decadent, creamy, and perfect for serving a crowd.

Ingredients

• Butter – for the roux to thicken the sauce and add richness.
• All-purpose flour – combined with butter to make the roux. For a gluten-free alternative, use 2 tablespoons of cornstarch instead of 1/4 cup of flour.
• Onion – yellow onion works well for a balanced flavor; Vidalia is a good choice if you prefer milder sweetness.
• Garlic – fresh minced cloves give the best flavor.
• Chicken broth – or substitute vegetable broth for a vegetarian version.
• Half-and-half – whole milk will work, but half-and-half gives a creamier sauce.
• Salt, black pepper, and fresh thyme – to season the sauce.
• Yukon Gold potatoes – thinly sliced. Yukon Golds are creamy and melt-in-your-mouth after baking; russets can be used but yield a different texture.
• Sharp cheddar cheese – freshly grated for best melting and flavor; sharp cheddar provides bold taste.
• Gruyere cheese – a nutty, aged Swiss-style cheese that complements the cheddar. Swiss can be used if preferred.

Instructions

Step-by-step photos are included in the gallery to guide you visually. For precise ingredient quantities and times, see the recipe card below.

Make the creamy sauce

1. Cook the aromatics. Melt butter in a large skillet over medium-high heat. Add diced onion and cook 4–5 minutes until softened. Add minced garlic and cook 1 more minute.
2. Add the flour. Sprinkle flour evenly over the onions and garlic and cook 1–2 minutes to remove the raw flour taste.
3. Combine with broth. Slowly whisk in the chicken or vegetable broth until smooth.
4. Make it creamy. Reduce heat to medium-low and gradually stir in the half-and-half (or milk). Increase heat slightly if needed to bring the mixture to a gentle boil while stirring.
5. Season and set aside. Stir in salt, black pepper, and fresh thyme. Remove from heat and keep the sauce warm while you prepare the potatoes.

Assemble and bake

1. Slice the potatoes. Thinly slice potatoes using a sharp knife or mandoline for even, quick cooking.
2. Prepare the baking dish. Grease a 9″ x 13″ casserole dish with butter or cooking spray.
3. Layer the casserole. Place one-third of the sliced potatoes in the bottom of the dish and sprinkle with about 1/2 teaspoon salt. Pour one-third of the sauce over the potatoes, then sprinkle 1/2 cup shredded cheddar and 1/2 cup shredded gruyere. Repeat this sequence two more times, reserving remaining cheese for the top.
4. Bake covered. Cover the dish with foil and bake at 350°F for 45 minutes.
5. Finish uncovered. Remove the foil, top with the remaining cheese, and bake another 20–30 minutes until the potatoes are tender and the cheese is melted and bubbly.
6. Broil for color. If desired, broil on high 2–3 minutes to brown the cheese, watching closely to prevent burning.
7. Rest and serve. Let the casserole rest 15 minutes before slicing to allow the sauce to set. Garnish with chopped parsley if you like.

Recipe notes

• Slicing: Thin, even slices ensure consistent cooking. A mandoline speeds the process, but use a sharp knife if you prefer.
• Temper the dairy: Let half-and-half sit at room temperature for about 15 minutes before adding; very cold dairy slows thickening.
• Freshly shred cheese: Pre-shredded cheeses often contain anti-caking agents that can affect melting. Grate cheese from a block for the best texture and flavor.
• Add subtle heat: A dash of hot sauce or 1/2 teaspoon cayenne in the sauce can enhance depth without making the dish spicy.
• Gluten-free option: Replace 1/4 cup flour with 2 tablespoons cornstarch to thicken the sauce.
• Servings: This recipe serves roughly 8–10 as part of a holiday meal with other sides, or 6–8 if it’s the primary side dish.

More side dish recipes

Here are a few additional side dishes to complement these potatoes: