This Sweet Potato and Cranberry Gratin began as a quiet experiment the winter I wanted something that felt like holiday and home at the same time. I wanted the warm, silky texture of a gratin but with a bright lift so the dish did not feel heavy. The first time I made it, I layered tender boiled sweet potato slices with a scattering of fresh cranberries and a lightly spiced cream, and the result was a beautiful balance of sweet, tart, and savory textures. It quickly became a requested side at family dinners. My parents asked for the recipe, my neighbor asked for second helpings, and I tucked a small corner piece away for myself before the rest was gone.

What makes this version special is the contrast. The sweet potato offers a velvet mouthfeel while the cranberries add a jewel-like acidity that cuts through richness. Using Gruyère gives a nutty, slightly savory finish that melts into the cream, while a crisp breadcrumb top brings the final texture contrast. I discovered the best proportions after several tries. The brown sugar heightens the sweet potatoes without making the whole dish cloying, and a teaspoon of cinnamon makes the aroma sing when it comes out of the oven. This is the kind of side that looks elegant on a holiday table but is simple enough for a weeknight celebration.

Ingredients

• Sweet potatoes, 2 pounds: Choose firm, evenly sized potatoes so slices cook uniformly. I prefer Beauregard or Garnet varieties for their balance of sweetness and texture. Peel with a swivel peeler and slice to approximately one quarter inch thickness for even layering.
• Fresh cranberries, 1 cup: Look for plump, glossy berries in the produce section. Fresh cranberries provide a bright tartness that canned jellies cannot replicate. Rinse and pick through to remove any soft berries.
• Heavy cream, 1 cup: Full fat cream gives a silky mouthfeel and helps create a custard-like binding between layers. If you prefer a lighter dish, half and half may be used but expect a slightly less rich finish.
• Shredded Gruyère, 1 cup: Gruyère melts smoothly and adds a nutty, savory depth. If you cannot find Gruyère, a good quality Swiss cheese is an acceptable substitute. Shred from a block rather than using pre-shredded for the best melt.
• Breadcrumbs, 1/2 cup: Use fresh breadcrumbs for a crisp, toasty topping. Panko gives extra crunch if you prefer more texture. For a gluten free option, substitute gluten free crumbs or crushed toasted almonds.
• Brown sugar, 1/4 cup: Light brown sugar adds warmth and a hint of molasses. It enhances the sweet potato flavor without overpowering the tart cranberries.
• Cinnamon, 1 teaspoon: Ground cinnamon warms the filling and plays nicely with the brown sugar and sweet potato flavors. Freshly ground is best for aroma.
• Salt and pepper: Season to taste. I recommend starting with 1/2 teaspoon fine salt in the cream mixture and adjusting after baking if desired.
• Butter or nonstick spray for greasing: A thin smear of butter or a quick spray ensures easy serving and a little additional butter flavor on the edges.

Instructions

Preheat the oven: Set the oven to 375 degrees Fahrenheit. Position a rack in the center so the top browns evenly. Lightly grease a 9 by 13 inch baking dish with butter or spray. A ceramic or metal dish both work well; ceramic will retain heat and keep the gratin warm longer when served. Cook the sweet potatoes: Place the peeled and sliced sweet potatoes in a large pot of cold salted water and bring to a gentle boil. Starting in cold water helps even cooking. Boil until the slices are just tender when pierced with the tip of a knife, approximately 10 to 15 minutes depending on thickness. Do not overcook; they should hold their shape because they will finish in the oven. Drain and arrange the first layer: Carefully drain the sweet potatoes and let them steam briefly in the colander to remove excess surface moisture. Arrange half of the slices in a single even layer in the prepared baking dish, overlapping slightly so the layer is compact and will absorb the cream evenly. Add cranberries and cream mixture: Scatter half of the fresh cranberries over the first sweet potato layer. In a medium bowl whisk together the heavy cream, brown sugar, cinnamon, 1/2 teaspoon salt, and a generous grind of black pepper. Pour half of this cream mixture evenly over the potatoes and cranberries so the liquid settles into the layers. Repeat layers and top: Repeat with the remaining sweet potatoes and cranberries, and pour the remaining cream mixture over the top. Sprinkle the shredded Gruyère evenly across the top, then finish with the breadcrumbs. For extra crispiness, dot the breadcrumbs with a teaspoon or two of melted butter or a light spray of oil. Bake until golden and bubbly: Bake at 375 degrees Fahrenheit for 30 to 35 minutes. Look for the top to be golden brown and bubbling around the edges. If the top browns too quickly before the interior is set, tent loosely with foil for the last 10 minutes and finish uncovered for the final 5 minutes to restore color. Rest and serve: Allow the dish to rest for 5 to 10 minutes after removing from the oven. Resting lets the cream settle and makes slices easier to serve. Serve warm as a side to roasted poultry or a holiday centerpiece.

Storage Tips

Transfer leftovers to an airtight container and refrigerate within two hours of baking. For best texture, consume within 48 hours. To freeze, cool completely, wrap tightly in a double layer of foil or place in a freezer safe dish, and store up to three months. Reheat from thawed in a 350 degrees Fahrenheit oven until warmed through, about 20 minutes, or reheat covered in the microwave in short intervals, then finish uncovered to crisp the topping.

Ingredient Substitutions

For a gluten free version, replace breadcrumbs with crushed toasted gluten free crackers or a mixture of ground almonds and gluten free panko. To make it dairy free, use a plant based heavy cream alternative and a dairy free melting cheese; texture will be slightly different but the gratin will remain comforting. If Gruyère is unavailable, good substitutes include Emmental or a mild cheddar for similar melting properties. For less sweetness, reduce the brown sugar to 2 tablespoons and increase the cinnamon if you like a spicier aroma.

Serving Suggestions

Serve alongside roasted turkey, honey glazed ham, or seared pork chops. For a vegetarian main, present the gratin with a crisp winter salad of arugula, toasted pecans, and a citrus vinaigrette. Garnish with a few fresh cranberries and a sprinkle of finely chopped parsley for color. This gratin also pairs nicely with a glass of medium bodied white wine or a lightly spiced cider.

Cultural Background

Gratin style baking originates from French home cooking where thinly sliced vegetables are baked with cream and cheese until golden on top. This version adapts that tradition to American holiday flavors by featuring sweet potato and fresh cranberries, both staples in winter produce markets. The use of Gruyère nods to classic gratins while brown sugar and cinnamon bring American seasonal character to the dish.

Seasonal Adaptations

In autumn and winter use fresh cranberries for brightness. In late spring and summer you can swap cranberries for roasted cherry tomatoes or a tart stone fruit when in season. For a spring brunch twist, reduce the brown sugar and add fresh herbs such as thyme or sage into the cream for an herbaceous finish.

Meal Prep Tips

Assemble the gratin up to 24 hours in advance, cover, and refrigerate. Bring to room temperature for 20 minutes before baking and increase bake time by 5 to 10 minutes if starting cold. Portion into individual ramekins for single serve reheating and serving convenience. Use ceramic ramekins and bake a few minutes longer until bubbling and the top is golden.

This gratin is one of those dishes that becomes part of your kitchen rotation because it is both forgiving and impressive. It rewards small touches like fresh shredded cheese and a light buttered breadcrumb topping. I hope you enjoy making it as much as my family has enjoyed eating it.