This creamy garlic butter sweet potato bake has been my go-to side dish for holiday meals and cozy weeknights alike. I first put this combination together on a rainy November afternoon when I wanted something richer than roasted sweet potatoes but easier than a gratin. The tender, thin slices soak up a garlic-infused cream that melts into the layers, creating a silky texture with just the right amount of bite from the Parmesan and the stretchy finish of mozzarella. It’s the kind of dish that fills the kitchen with a warm, garlicky aroma and instantly brings people to the table.

I discovered early on that the success of this dish hinges on a few small decisions: slicing the sweet potatoes thin and evenly, gently warming the cream with garlic to coax out flavor without burning, and letting the assembled dish rest briefly after baking so the cream thickens and the layers settle. Over the years, this bake has become the centerpiece of several family dinners — guests often ask for the recipe, and I love how it offers both comfort and an elegant presentation without a lot of fuss.

Ingredients

• Sweet potatoes: 4 medium (about 2 pounds). Choose firm, smooth-skinned tubers without soft spots. Even-sized potatoes make uniform slices, which ensures consistent baking. I prefer orange-fleshed varieties for sweetness and color.
• Heavy cream: 1 cup. Full-fat cream yields the richest texture and helps bind the layers into a silky custard. If you prefer lighter fare, you can substitute half-and-half, but the final result will be less decadent.
• Unsalted butter: 1/2 cup, melted. Unsalted gives you control over seasoning; use a high-quality European-style butter for a creamier mouthfeel.
• Garlic: 4 cloves, minced. Fresh garlic is essential — it infuses the cream with aromatic depth. Adjust to taste but add sparingly while sautéing to avoid bitterness.
• Seasonings: 1 teaspoon salt, 1/2 teaspoon black pepper, 1 teaspoon dried thyme, 1 teaspoon paprika. These bring savory balance and a gentle herbaceous note; smoked paprika adds depth if you prefer a smoky edge.
• Parmesan cheese: 1/2 cup, finely grated. Adds salty, umami lift between layers; choose Parmigiano-Reggiano for the best flavor.
• Mozzarella cheese: 1/2 cup, shredded. A melting top layer that becomes golden and bubbly; whole-milk mozzarella works best for stretch and creaminess.
• Fresh parsley: Chopped, for garnish. Brightens the finished dish and adds a fresh contrast to the richness.

Instructions

Preheat and prepare baking dish: Preheat the oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish with cooking spray or a thin layer of butter to prevent sticking and to help the edges caramelize. A metal pan will brown edges faster, while ceramic gives gentler heat. Sauté the garlic and combine the cream: In a small saucepan over medium heat, melt the unsalted butter. Add the minced garlic and sauté for about 30–60 seconds until fragrant — avoid browning the garlic, which can make it taste bitter. Remove from heat and stir in the heavy cream, salt, pepper, dried thyme, and paprika. Stir until combined; the mixture should be warm but not boiling so it gently infuses with garlic flavor. Slice the sweet potatoes: Peel the sweet potatoes and slice them thinly, about 1/8 to 1/4 inch thick. A mandoline or a chef’s knife works; uniform slices ensure even cooking. If using a mandoline, wear a cut-resistant glove and work carefully. Pat slices dry if they’re wet to avoid a watery bake. Layer the first half: Arrange half of the sweet potato slices in an even layer across the bottom of the prepared dish, slightly overlapping each slice like roof tiles. Pour half of the garlic butter cream over the first layer, using the back of a spoon to help distribute the liquid so it reaches between slices. Sprinkle half of the grated Parmesan evenly across the top to add a savory backbone between layers. Finish layering: Repeat with the remaining sweet potato slices, pour the remaining cream mixture evenly over the top, and finish with the remaining Parmesan. Gently press down on the top so the cream settles between the layers. Cover tightly with aluminum foil to trap steam and promote tenderizing. Bake covered, then top with mozzarella: Bake the covered dish in the preheated oven for 30 minutes. Remove the foil, evenly scatter shredded mozzarella over the surface, and return the dish uncovered for an additional 25–30 minutes. The bake is done when a knife or fork slides through the potatoes easily and the cheese is bubbly and golden with small brown spots. Rest and garnish: Remove from the oven and let rest for 5–10 minutes. Resting allows the cream to thicken and the slices to settle, making serving cleaner. Sprinkle with chopped fresh parsley before serving for color and a bright herbal note.

Storage Tips

Allow the bake to cool to room temperature (no more than two hours) before refrigerating. Store in an airtight container or cover the baking dish tightly with plastic wrap and foil. Refrigerated leftovers keep well for up to 4 days. For longer storage, slice into portions, wrap each tightly in plastic wrap and foil, then freeze for up to 3 months. Reheat from frozen in a 350°F (175°C) oven for 20–30 minutes covered, then uncover to melt cheese and brown the top. For refrigerated portions, reheat in a 350°F oven for 10–15 minutes.

Ingredient Substitutions

If you want to lighten the dish, swap half the heavy cream for whole milk or half-and-half; remember the texture will be less luxurious. For a dairy-free and vegan version, use a plant-based heavy cream (coconut cream or a cashew cream works well) and replace butter with olive oil or a vegan butter substitute, and use vegan Parmesan and mozzarella. If you want more herb aroma, swap dried thyme for fresh thyme leaves (use about 1 tablespoon fresh) added to the cream. For smoky depth, use smoked paprika instead of sweet paprika.

Serving Suggestions

This pairs beautifully with roasted or grilled proteins — roast chicken, pork loin, or a pan-seared salmon fillet are natural partners. For a vegetarian menu, serve with a crisp green salad dressed in a lemon vinaigrette to cut through the richness. Garnish with toasted walnuts or a sprinkle of chili flakes for contrast. Serve hot from the oven with crusty bread to soak up any remaining cream.

Cultural Background

While gratin-style casseroles are rooted in French culinary tradition, using sweet potatoes gives this dish a distinctly American twist. Sweet potatoes have long been integrated into Southern and holiday cooking in the United States, often appearing in casseroles or mashed preparations. This rendition borrows the layered, custardy technique of a classic gratin but celebrates the natural sweetness and texture of the sweet potato, creating a hybrid that feels both familiar and slightly elevated.

Seasonal Adaptations

In autumn and winter, add warming spices like a pinch of cinnamon or nutmeg to the cream for a seasonal touch; top with toasted pecans for crunch. In spring, swap some of the parsley for fresh chives or dill to brighten the dish. For holiday meals, scatter fried sage leaves and a drizzle of browned butter over the top just before serving to add nutty complexity.

Meal Prep Tips

Assemble the dish up to 24 hours in advance, cover, and refrigerate. This actually helps flavors meld and saves time on the day of serving — simply allow the dish to come to room temperature for 20 minutes before baking and add an extra 5–10 minutes to the covered baking time if it went into the oven chilled. Use shallow, single-serve containers for portioned prep that makes weekday reheating quick and easy.

Bring this dish to your next family dinner and watch how a simple combination of cream, butter, garlic, and cheese transforms humble sweet potatoes into something celebratory. It’s approachable enough for a weekday but elegant enough for company — and it always invites conversation at the table.