Sweet potato and leek gratin


Sweet potato and leek gratin

Need a healthy side dish to bring to the office pot luck or family holiday dinner? Nancy Waldeck, a chef at Cancer Wellness at Piedmont, suggests this sweet potato and leek gratin. It packs both a sweet and salty taste, and is sure to be a crowd pleaser.

You’re probably familiar with potatoes au gratin, but this recipe brings nutrition-packed sweet potatoes and leeks to the table. If you aren’t familiar with leeks, they are onion-like, leafy stalks packed with flavonoid antioxidants, fiber, vitamins and minerals. Chef Nancy also uses nonfat yogurt instead of cream to cut down on the dish’s fat and calories.


  • 2 lbs sweet potatoes, peeled, thinly sliced, divided

  • 1.5 lbs leeks, cut in half and thinly sliced, divided

  • 2 tbsp chopped fresh sage, divided

  • 1 tbsp chopped fresh rosemary, divided

  • 1 cup grated Gruyere, divided

  • 1 Granny Smith apple, peeled, cored and thinly sliced, divided

  • ¾ cup evaporated skim milk

  • 1 garlic clove, grated

  • 1 tsp salt

  • 1 tbsp unsalted butter

  • ½ cup nonfat plain yogurt (not Greek yogurt)

  • 1 tsp salt and ½ tsp freshly-ground black pepper to taste


  • Preheat the oven to 400 F.

  • Cover a gratin dish with nonstick spray. Arrange half of the sweet potatoes evenly in the dish. Top with half of the leeks, herbs, and ½ a cup of gruyere. Top with apple slices and sprinkle with the salt and freshly-ground pepper. Arrange remaining potato slices, followed by the leeks and apples. Sprinkle with remaining herbs.

  • Bring the milk, garlic and salt to simmer in heavy small saucepan (or in microwave) and pour evenly over the potato mixture. Season with salt and pepper, and dot with 1 tbsp of butter. 

  • Cover tightly with foil and bake until tender when pierced with a knife (about 30 minutes).

  • Reduce the oven to 350 F.

  • Remove the gratin from the oven; uncover and drizzle with yogurt. Sprinkle with remaining ½ cup cheese.

  • Continue baking, uncovered, until yogurt bubbles thickly at edges and top is browned (about 25 minutes).

  • Cool slightly and serve.

Check out more recipes and nutrition tips from Cancer Wellness experts.

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