Crunchy-Topped Sweet Potato and Cranberry Gratin

If you’ve ever wanted a side dish that feels a little fancy but is still totally doable, this sweet potato and cranberry gratin is it. It’s creamy and cozy, with tender sweet potato layers and little pops of tart cranberry that make every bite feel special.

I make this whenever I need a reliable crowd-pleaser for holiday tables, Sunday roasts, or those nights when I want dinner to feel a bit more “put together” without extra effort. And if you’re feeding picky eaters? Calling the cranberries “ruby sprinkles” weirdly helps more than it should.

Why You’ll Love Sweet Potato and Cranberry Gratin

You’ll love this gratin because it hits that perfect sweet-savory balance without feeling overly sweet. It’s creamy, comforting, and the cranberries add little bursts of tart flavor that keep every bite interesting. Gratin-style bakes have classic French roots (layered slices + cream + a golden top), and this version leans into a festive, seasonal twist that’s perfect for fall and winter meals.

Simple Ingredients

A handful of everyday staples come together to make this feel like a special-occasion side.

• Sweet potatoes: Naturally sweet and creamy when baked, they’re the star of the layers.
• Fresh or frozen cranberries: Adds bright tartness that balances the richness beautifully.
• Heavy cream: Creates that luscious gratin texture and helps soften the layers.
• Milk: Lightens the cream just enough so it doesn’t feel too heavy.
• Garlic: Adds a gentle savory backbone without overpowering.
• Thyme: A cozy herb that pairs perfectly with sweet potatoes.
• Salt: Brings out the sweetness and keeps the flavor balanced.
• Black pepper: Adds a subtle warmth and bite.
• Nutmeg: Just a pinch makes the cream taste extra cozy and “holiday.”
• Parmesan: Helps the top brown and adds savory depth.
• Breadcrumbs: Gives that crunchy, golden finish everyone fights over.
• Butter: Helps the topping crisp up and taste rich.

Servings and Timing

Servings: 8
Preparation time: 20 minutes
Cook time: 55 minutes
Total time: 1 hour 15 minutes

Recommended Equipment

Sharp chef’s knife or mandoline slicer
Cutting board
Large mixing bowl
Small saucepan
Whisk
9×13-inch baking dish (or similar gratin dish)
Measuring cups and spoons
Foil
Oven mitts

What is Needed

• 3 lbs sweet potatoes, peeled and thinly sliced
• 2 cups fresh or frozen cranberries
• 1 1/2 cups heavy cream
• 1/2 cup milk
• 2 cloves garlic, minced
• 1 tsp fresh thyme leaves (or 1/2 tsp dried thyme)
• 1 1/4 tsp salt
• 1/2 tsp black pepper
• 1/8 tsp ground nutmeg
• 1/2 cup grated parmesan cheese (Affiliate)
• 1/2 cup breadcrumbs (panko or regular)
• 2 tbsp butter, melted

How to Make Sweet Potato & Cranberry Gratin

1. Preheat the oven to 190°C (375°F) and lightly butter a 9×13-inch baking dish.
2. Slice the sweet potatoes thinly (a mandoline makes this fast and even) and place them in a large bowl.
3. Add the cranberries to the bowl and gently toss so they’re evenly mixed through the slices.
4. In a small saucepan over low heat, warm the heavy cream and milk with the minced garlic, thyme, salt, pepper, and nutmeg until just steaming (don’t boil). Whisk well.
5. Pour the warm cream mixture over the sweet potato and cranberry mixture and gently toss to coat.
6. Layer everything into the baking dish, spreading it out evenly and pressing down lightly so the cream settles between layers.
7. Cover tightly with foil and bake for 40 minutes.
8. While it bakes, mix parmesan, breadcrumbs, and melted butter in a small bowl until the crumbs look evenly coated.
9. Remove foil, sprinkle the topping evenly over the gratin, and bake uncovered for 15 minutes more (or until golden and bubbling).
10. If you want extra browning, broil for 1–2 minutes at the end, just watch closely.
11. Rest for 10 minutes before serving so the layers set nicely.

What To Serve With This Recipe

For something fresh and snappy alongside all that creamy goodness, link to my honey garlic butter Brussels sprouts. They’re fast, family-friendly, and the perfect green side for this gratin.

• Roast chicken or turkey
• Glazed ham
• Pork tenderloin
• Garlic green beans or broccolini
• Simple arugula salad with vinaigrette
• Pan gravy or a light mustard cream sauce

Top Tips

• Slice evenly: Thin, uniform slices cook at the same rate, so you don’t get crunchy surprises.
• Family-friendly cranberry trick: If you are unsure if guests like cranberries, stir in just 1 cup of cranberries and sprinkle the rest on top for “pretty.”
• Don’t boil the cream: Warming gently helps infuse the garlic and thyme without splitting.
• Make-ahead win: Assemble the gratin (without topping), cover, and refrigerate up to 24 hours. Add topping right before baking.
• Let it rest: That 10-minute rest makes it easier to slice and keeps the gratin creamy instead of runny.

Recipe Variations

• Add pecans or walnuts: Sprinkle chopped nuts over the topping for extra crunch.
• Swap herbs: Rosemary is lovely if you want something more piney and bold.
• Add onions: Thinly sliced shallots layered in bring sweet-savory depth.
• Go extra cheesy: Add a layer of gruyère or cheddar for a richer gratin vibe.
• Make it dairy-light: Use half-and-half instead of heavy cream (it’s slightly less rich, but still tasty).

How to Store and Reheat

• Store leftovers in an airtight container in the fridge for up to 4 days.
• Reheat in the oven at 175°C (350°F) covered with foil for 15–20 minutes, then uncover for 5 minutes to re-crisp the top.
• Microwave reheating works for speed, but the topping will soften. Pop it under the broiler for a minute if you want the crunch back.
• Freezing is possible, but the cream sauce can change texture slightly; if you freeze, thaw overnight in the fridge, and reheat in the oven.

Sweet Potato and Cranberry Gratin

Michelle

A creamy, cozy sweet potato gratin dotted with tart cranberries and finished with a golden, buttery parmesan crumb topping.

Print Recipe Pin Recipe

Prep Time 20 minutes mins

Cook Time 55 minutes mins

Total Time 1 hour hr 15 minutes mins

Course Side Dish

Servings 8

Equipment

• Sharp chef’s knife or mandoline slicer
• Cutting board
• Large mixing bowl
• Small saucepan
• Whisk
• 9×13-inch baking dish (or similar gratin dish)
• Measuring cups and spoons
• Foil
• Oven mitts

Ingredients

  

• 3 lbs sweet potatoes peeled and thinly sliced
• 2 cups fresh or frozen cranberries
• 1 1/2 cups heavy cream
• 1/2 cup milk
• 2 cloves garlic minced
• 1 tsp fresh thyme leaves or 1/2 tsp dried thyme
• 1 1/4 tsp salt
• 1/2 tsp black pepper
• 1/8 tsp ground nutmeg
• 1/2 cup grated parmesan cheese
• 1/2 cup breadcrumbs panko or regular
• 2 tbsp butter melted

Instructions

 

• Preheat the oven to 190°C (375°F) and lightly butter a 9×13-inch baking dish.
• Slice the sweet potatoes thinly (a mandoline makes this fast and even) and place them in a large bowl.
• Add the cranberries to the bowl and gently toss so they’re evenly mixed through the slices.
• In a small saucepan over low heat, warm the heavy cream and milk with the minced garlic, thyme, salt, pepper, and nutmeg until just steaming (don’t boil). Whisk well.
• Pour the warm cream mixture over the sweet potato and cranberry mixture and gently toss to coat.
• Layer everything into the baking dish, spreading it out evenly and pressing down lightly so the cream settles between layers.
• Cover tightly with foil and bake for 40 minutes.
• While it bakes, mix parmesan, breadcrumbs, and melted butter in a small bowl until the crumbs look evenly coated.
• Remove foil, sprinkle the topping evenly over the gratin, and bake uncovered for 15 minutes more (or until golden and bubbling).
• If you want extra browning, broil for 1–2 minutes at the end just watch closely.
• Rest for 10 minutes before serving so the layers set nicely.

Notes

If using frozen cranberries, no need to thaw; just stir them in straight from frozen.
For extra-even cooking, keep slices thin and consistent (a mandoline helps).
Assemble ahead (without topping) up to 24 hours; add topping right before baking for best crunch.

Keyword Sweet Potato and Cranberry Gratin