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These Vegan Potatoes Au Gratin must be on your holiday tables this year! They’re perfectly creamy, cheesy, and guaranteed to please a crowd. Don’t be surprised if there aren’t any leftovers.
If you are planning your Thanksgiving and holiday menus, be sure to check out our 31 Must-Try Vegan Thanksgiving Recipes and our ultimate collection of 50+ of the Best Vegan Thanksgiving Recipes. From main dishes, vegan side dishes, desserts, holiday drinks, appetizers, and even genius ways to repurpose your Thanksgiving leftovers – we’ve got you covered.
Origin of Potatoes Au Gratin
It is believed that potatoes au gratin originated in the Dauphine region of France and is
classically referred to as gratin Dauphinois. The term au gratin is based on the French word, grater, meaning ‘to grate.’
This is in loose reference to the crispy scraps left on the bottom of a casserole dish after baking. The potatoes au gratin dish replicates those tasty, crispy bits with thinly sliced potatoes, cheese, milk, and butter. In the United States, potatoes au gratin are commonly confused with scalloped potatoes, though scalloped potatoes should be prepared without the cheese.
This version of potatoes au gratin is completely vegan but tastes almost identical to the popular potato casserole dish!
Ingredients You’ll Need
- Yukon Gold Potatoes – In our opinion, Yukon gold potatoes are the best potatoes to use when making vegan potatoes au gratin. They’re easy to cook, have a thin skin that doesn’t require peeling, and are high in starch, making an extra creamy potato dish.
- Vegan Butter – To make the richest tasting savory cream sauce to bake your potatoes in, we recommend using vegan butter. If needed, you can substitute vegetable oil or olive oil. If you are oil-free, try our Oil-Free Vegan Scalloped Potatoes.
- Onion and Garlic – Finely diced onion and garlic are the base of the sauce and provide essential flavor to the potatoes au gratin. We used white onion, but you can opt for yellow onion if you have them on hand. Avoid using red onions – they are too sharp and best reserved for dishes like Easy Homemade Guacamole and Esquites-Inspired Pasta Salad.
- Aromatics – In addition to salt and pepper, we highly recommend using fresh thyme and rosemary as they are much more flavorful than dried and are the perfect seasonings to use in this vegan side dish.
- All-Purpose Flour – Flour is used to make a roux and thicken our vegan cream sauce. We have not tested these vegan potatoes au gratin with an alternative flour. If you are gluten-free, you may enjoy our Corn Flake Crusted Scalloped Potatoes recipe.
- Non-Dairy Milk – It is important to use unsweetened milk in this savory vegan side dish. If you are using store-bought vegan milk, we recommend tasting it before using it in your cream sauce. Some unsweetened milk in stores has an artificially sweet taste even though they are labeled unsweetened and will make your potatoes au gratin oddly sweet.
- Vegan “Chicken” Broth – Helps make these potatoes perfectly savory. We like to use Better than Bouillon Vegan Chicken Base that we buy from our local health store. If you cannot find it in stores, it is available on Amazon, or opt for your favorite vegetable broth.
- Nutritional Yeast – A staple in our vegan kitchen! Nutritional yeast makes these potatoes cheesy tasting without dairy. We use and recommend Braggs.
- Vegan Cheese – Potatoes au gratin is traditionally made with dairy cheeses. To replicate these flavors, we make these potatoes with a combination of vegan mozzarella cheese and vegan parmesan. Use your favorite brands!
How to Make Potatoes Au Gratin with a Vegan Cheese Sauce
- Thinly slice the potatoes. Using a mandolin, thinly slice the potatoes into ⅛” thick rounds. Submerge the sliced potatoes in a large bowl of cold water to prevent browning. Set aside while you prepare the vegan cheese sauce.
- Cook the onions and aromatics. Melt the vegan butter in a large skillet over medium heat. Add the diced onion and salt. Cook, occasionally stirring, until the onion is lightly browned, 5-6 minutes. Add the garlic, thyme, and rosemary, and cook for another 1-2 minutes.
- Prepare a simple vegan roux. Reduce the heat to medium-low and add the all-purpose flour. Cook for 1-2 minutes, constantly stirring, until a thick paste forms. Slowly pour in the oat milk, continuing to whisk until smooth.
- Create the vegan cheese sauce. Once fully incorporated with no lumps, stir in the “chicken” broth. Then add the black pepper, nutmeg, nutritional yeast, and vegan parmesan. Stir occasionally until the parmesan is melted and the sauce coats the back of a spoon, resembling a gravy-like consistency. Remove from heat and taste, adding more salt or pepper as needed.
- Layer the potatoes in the baking dish. Drain the potato slices and layer 1/3 in your prepared baking dish. Add 1/3 of the cream sauce on top and spread it evenly with a spoon or spatula. Top with a sprinkle of salt, pepper, and vegan mozzarella cheese. Continue to layer the potatoes, cheese sauce and salt, pepper and vegan mozzarella cheese until you use up all of the potatoes and cream sauce.
- Bake. Cover with aluminum foil and bake for 30 minutes. Remove the foil and bake for another 30 minutes, uncovered.
- Serve. Allow the potatoes to cool for 10-15 minutes before serving. Top with fresh chives and enjoy!
Tips for Success
- Use a mandolin to thinly slice the potatoes. This is by far the easiest way to slice the potatoes paper thin. If you do not have a mandolin, the next best way to thinly slice the potatoes is to use a large-cup food processor with the slicing blade attachment. As a last resort, you can slice the potatoes using a knife, but take time to cut them uniformly. If the potatoes are cut thicker or unevenly, a much longer bake time will be needed.
- Lightly grease the casserole dish. This will prevent the bottom layer from sticking and make serving quick and simple.
- Bake covered! Tightly covering the vegan potatoes au gratin for the first 30 minutes of baking steams the potatoes and helps them cook through until fork tender. If you skip this, the potatoes will take significantly longer to bake through.
Vegan potatoes au gratin are the perfect side dish for holidays and family dinners. Here are a few of our favorite main dishes that pair perfectly with these vegan cheesy potatoes.
- Healthy Cream of Mushroom Soup
- Roasted Butternut Squash and Pear Soup
- Easy Veggie Meatloaf
- Breaded Cauliflower Steaks
- Vegetable Wellington with Lentils and Mushrooms
- Vegan Portobello Mushroom Steaks
This vegan side dish will store well in the fridge for up to 5 days. Store in an airtight container for optimal freshness, or tightly cover the baking dish with cling wrap or a lid.
We have not attempted to freeze these potatoes au gratin but believe it would freeze well. If attempting to freeze, wait until the side dish is completely cooled to room temperature.
More Vegan Side Dishes You May Enjoy:
- Vegan Green Bean Casserole
- Vegan Buttermilk Biscuit Stuffing
- Maple Roasted Acorn Squash
- Thanksgiving Stuffed Mashed Potato Balls (Vegan)
- Garlic Herb Dinner Rolls