Sweet potatoes roasted to perfection in a creamy herb sauce, covered with melty cheese and crispy panko breadcrumbs. The coziest side dish that no one will ever guess is actually pretty healthy!

Why You’ll Love This Healthy Sweet Potato Au Gratin

This isn’t your grandma’s heavy, cream-loaded au gratin (though I love hers too!). I lightened up this classic comfort food using just enough cheese to keep every bite irresistible. The result? A delicious sweet potato dish that isn’t too heavy.

Crowd-pleasing — feeds 6-8 as a side dish

Healthier than traditional au gratin — no heavy cream, butter, or refined ingredients

Naturally sweet and savory — sweet potatoes pair perfectly with garlic, cinnamon, and parmesan

Beautiful enough for the holiday table — those upright potato slices are stunning

Easy to customize — vegan? Gluten-free? Got you covered with simple swaps

If you love cozy holiday side dishes, you’ll also want to try my Cauliflower Mashed Potatoes, Healthy Sweet Potato Casserole, Crispy “Cheesy” Broccoli Casserole, and Roasted Carrots with Tahini Sauce. Or browse all my healthy side dishes here.

Ingredients You’ll Need

Here’s what makes this healthy sweet potato au gratin work — simple, wholesome ingredients you probably already have:

1-2 large sweet potatoes — try to pick round ones similar in size
½ cup milk — regular or non-dairy works fine
¾ cup grated parmesan cheese — I recommend freshly grated
Pantry seasonings — salt, pepper, cinnamon, garlic powder
Panko breadcrumbs — for that crispy golden topping
Optional: shredded mozzarella — for extra cheesy flavor

Let’s Make Some Healthy Sweet Potato Au Gratin!

Arranging the potatoes is the trickiest part (I shared a process shot below to help). I love using an oval dish, but a rectangle or square works just as well. The key is getting the potatoes upright, touching the bottom of the pan, and poking out the top so they crisp up beautifully in the oven. Pack them close enough that they support each other and won’t tip over.

For the prettiest presentation, look for sweet potatoes that are round and roughly the same size — they’ll line up neatly without any awkward gaps. That said, once everything’s buried under melty cheese, no one’s inspecting shapes. So really, don’t stress.

No need to peel the sweet potatoes (I never do), but it’s totally your call.

Any dairy-free milk works here. I love cashew or oat milk because they’re extra creamy but almond milk works great too. Just avoid anything thin or sweetened.

Cheese tip: I pull a few potatoes apart and tuck extra cheese into the gaps so every bite is cheesy. Use as much (or as little) as you like, and vegan cheese works great too.

This is the ultimate cozy side dish and easily feeds a crowd. Hope you love it as much as we do! Questions? Drop a comment below or DM me on Instagram.

Frequently Asked Questions

Can I make this sweet potato au gratin vegan?

Absolutely! Use non-dairy milk (which the recipe already calls for) and swap in your favorite vegan parmesan and mozzarella. The result is just as creamy and satisfying.

Do I need to peel the sweet potatoes?

Nope! The skins are thin, nutritious, and add nice texture. Just give them a good scrub. If you prefer peeled, that’s totally fine too.

What’s the best non-dairy milk for au gratin?

Thick, unsweetened options work best. Plant-based creamers (like Lavva), full-fat coconut milk, unsweetened oat milk, and thick almond milk all give you that creamy result. Avoid anything sweetened or watery.

Can I make this ahead of time?

Yes! Assemble the dish up to 24 hours in advance, cover, and refrigerate. Add a few extra minutes to the bake time when you’re ready to cook.

How do I store leftovers?

Store leftovers in an airtight container in the fridge for up to 4 days. Reheat in a 350°F oven for 10-15 minutes to bring back the crispy top.

Can I freeze sweet potato au gratin?

This dish is best fresh, so I don’t recommend freezing this recipe.

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