Sweet Potato and Yukon Gold Bake

Festive crispy baked sweet potatoes and yukon gold potatoes on a bed of caramelized onions. Perfect for a holiday side!

Sweet Potato Yukon Gold Bake
Elise Bauer

Looking for a special holiday side? Here's a festive dish that alternates the flavors and colors of vibrant sweet potatoes with buttery yukon gold potatoes, all sitting on a bed of caramelized onions.

I actually started out to make a gratin, more in the spirit of our gruyere potatoes, perhaps with a breadcrumb topping. But as I experimented with the recipe, the wonderful flavors of the sweet potatoes and potatoes seemed to get lost in the rich toppings.

Sweet Potato Yukon Gold Bake
Elise Bauer

So the toppings got chucked in favor of a more naked gratin, the un-gratin. The gratin without the gratin part. A rainbow hasselback sweet potato and potato bake.

It's so pretty! I found a big beautiful purple sweet potato at the market that contrasts beautifully with the garnet yam and yellow yukon golds. Sweet potatoes come in many shades, so pick a variety.

Sweet Potato and Yukon Gold Bake

Prep Time 15 mins
Cook Time 85 mins
Total Time 100 mins
Servings 6 to 8 servings

Look for sweet potatoes that are small in diameter, long, and uniform in shape.

Going vegan? Swap out the butter in step 3 with olive oil.


For the caramelized onions:

  • 2 tablespoons extra virgin olive oil

  • 4 cups sliced onions (1/8 to 1/4-inch slices)

  • 1 teaspoon fresh thyme, minced

  • 1/2 teaspoon kosher salt

For the sweet potatoes and Yukon golds:

  • 2 pounds sweet potatoes mixed in color if available, peeled and sliced into 1/8-inch thick rounds

  • 2 pounds Yukon gold potatoes peeled, and sliced into 1/8-inch thick rounds

  • 2 tablespoons melted butter

  • 1 teaspoon kosher salt

  • 1/4 teaspoon freshly ground black pepper

  • Sprigs fresh thyme


  1. Caramelize the onions:

    Heat olive oil in a large, thick-bottomed pot on medium heat. Add the sliced onions, toss to coat, lower the heat to medium low and cover. Let cook for 15 to 20 stirring occasionally, until completely softened.

    Elise Bauer
    Elise Bauer

    Then increase the heat to medium high and cook uncovered until golden brown. Remove from heat and stir in salt and thyme.

  2. Preheat the oven to 400°F.
  3. Peel and slice the sweet potatoes and Yukon golds:

    Try to make them uniform in size.

    Place the slices in a bowl of water while you are prepping them to prevent them for discoloring. If using purple sweet potatoes, keep the slices in a different bowl of water (the color bleeds).

    Drain the slices, place them in a bowl.

  4. Line the baking dish with onions, sweet potato and potato slices:

    Place the caramelized onions in an even layer over the bottom of a 9 x 12-inch rectangular or oval casserole dish.

    Elise Bauer
    Elise Bauer

    Arrange slices of sweet potatoes and Yukon Gold potatoes in rows on top of the caramelized onions.

    Brush with melted butter, sprinkle with salt and pepper.

  5. Cover with foil and bake:

    Bake for 45 minutes, until the potatoes are cooked through.

  6. Remove the foil, continue to bake:

    Bake an additional 15 minutes until the edges are crispy and browned.

    Elise Bauer

    Sprinkle with a little more salt and pepper. Garnish with sprigs of fresh thyme. Serve immediately.

Nutrition Facts (per serving)
313 Calories
7g Fat
59g Carbs
7g Protein
Show Full Nutrition Label Hide Full Nutrition Label
Nutrition Facts
Servings: 6 to 8
Amount per serving
Calories 313
% Daily Value*
Total Fat 7g 9%
Saturated Fat 2g 12%
Cholesterol 8mg 3%
Sodium 368mg 16%
Total Carbohydrate 59g 21%
Dietary Fiber 8g 28%
Total Sugars 14g
Protein 7g
Vitamin C 39mg 196%
Calcium 87mg 7%
Iron 2mg 13%
Potassium 1335mg 28%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
Nutrition information is calculated using an ingredient database and should be considered an estimate. In cases where multiple ingredient alternatives are given, the first listed is calculated for nutrition. Garnishes and optional ingredients are not included.