This recipe is proof that the simplest dishes can be the most stunning. Thinly sliced sweet potatoes are beautifully layered, brushed with a nutty garlic and herb infused brown butter, and baked until the edges caramelize and the centers turn tender and custardy. A sprinkle of Parmesan adds just the right savory contrast to balance the potatoes’ natural sweetness.
It’s elegant enough for Thanksgiving or a dinner party, but simple enough for a cozy weekend dinner spread with a steak or roast chicken and a simple salad. The best part? You can bake it ahead!
Ingredient highlight
Sweet potatoes (yams)! are my complex carb of choice and one of my favorite veggies to always have on hand. I’ll often eat them as a snack or lunch with a fried egg and avocado. They’re loaded with fiber and potassium and high in vitamin B1, B6, A and C.
Servings 8
Prep Time 20 minutes 
Cook Time 1 hour Ingredients
- 6 tbsp salted butter
- 3 tbsp olive oil
- 1 clove garlic, grated
- 3 tbsp chopped fresh thyme or 2 tsp dried thyme
- ¾ tsp kosher salt
- Black pepper
- 3-3.25 lbs sweet potatoes, cut into 1/8 inch thick slices*
- ½ cup (about 2 oz) grated parmesan cheese, plus more for topping**
- Lemon wedges, optional
- *If you have one, use a mandolin to thinly slice the potatoes. It’s much faster, easier, and you’ll get more even slices.
- **Use any salty cheese! Parm, pecorino, gruyere, etc…or a mix.
- Note: ~ I tested this in a 9×13 and 12-inch cast-iron. You could also use a 10–12 inch round dish, or 2-2.5 quart oval dish.
- Feeding a smaller crowd? ~ Easily cut the recipe in half and bake it in a 8×8-inch baking dish.
Make-ahead options:
- Make the whole recipe up to 2 days ahead. Reheat in a 350F oven for 20–25 minutes, until warmed through. Increase to 425F convection for the last 10 minutes to recrisp. You can brush more warm brown butter (or plain butter) over the top right before serving, if you’d like.
- OR prep the components (recommended)– make the brown butter mixture and slice the sweet potatoes ahead. You can even arrange them in the baking dish/skillet ahead. Either way, let the sweet potatoes sit at room temp for 30 minutes before baking so they don’t go into the oven really cold. Warm the butter in the microwave to melt it before brushing over the potatoes.
Instructions
- Preheat the oven to 400F.
- In a small pot, melt the butter over medium. Once melted, continue to simmer until golden and nutty, about 3-4 minutes, swirling occasionally. The butter will start bubbling with big bubbles, then it will turn to very small foamy bubbles. Once that transition happens is when you can turn off the heat. You should see the milk solids at the bottom turned a golden color.
- Immediately stir in the olive oil, garlic, herbs, salt, and pepper. Set aside.
- In a 12-inch cast iron skillet, arrange the sweet potato slices upright in overlapping concentric circles (like dominoes, see video). Don’t stress about perfection — uneven layers look rustic and charming.
- Brush generously with most of the butter mixture, letting it seep between slices. Save a little bit of the butter to brush on at the end.
- Sprinkle the parmesan over top. Cover tightly with foil and bake for 40 minutes. Remove the foil and bake for 20-25 more minutes. During the last 10 minutes, brush the remaining butter over top and sprinkle with a dusting of parmesan.
- Let cool for at least 10 minutes or up to 30 minutes before serving. As it cools, the butter thickens a bit and soaks into the potatoes.
- Serve with lemon wedges (if using) – they help cut through the richness and sweetness of the potatoes.
Items you can prep ahead (optional)
- Chop 3 tbsp fresh thyme (or use dried)
- Make the brown butter mixture
- Thinly slice 3-3.25 lbs sweet potatoes into 1/8 inch thick slices
- Grate ½ cup (about 2 oz) parmesan cheese, plus more for topping
- Option to assemble and/or bake ahead (see recipe note)
Substitutions:
- To make vegan, use a vegan butter. Skip the cheese and sprinkle an extra ½ teaspoon salt on top.
- Use regular potatoes in place of sweet potatoes. Reduce the bake time (30 minutes covered, 15-20 minutes uncovered). You may want to add about ¼ cup of broth of cream to add moisture since regular white potatoes have less moisture.
Storage:
- Store leftovers in an airtight container in the fridge for up to 5 days.
Leftovers + Repurposing:
- Reheat in a 350F oven for 20–25 minutes, until warmed through. Increase the heat to 425F convection during the last 10 minutes to help recrisp the tops. You can brush more warm brown butter (or plain butter) over the top right before serving, if you’d like.
- The oven is the best way to reheat it, but you could also simply use a microwave for smaller portions. It won’t be as crisp, but it is still very delicious!
- Serve with steamed/sauteed greens and a couple of fried eggs on top.
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