Sweet Potato Gratin with Ham

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My Sweet Potato Gratin with Ham is savory, sweet, and oh-so delish! This one-dish entrée is perfect to serve at brunch, dinner, or a potluck. Great for holiday meals, including Easter!

Sweet Potato Gratin with Ham – Good for Easter or Anytime

Easter is normally an at-home holiday for us. However, our eldest son is running the Boston Marathon the day after Easter and we’re flying out to cheer him on. So, we’ll be enjoying Easter dinner in a restaurant this year.

If we were spending the holiday at home, this Sweet Potato Gratin with Ham would definitely be on the menu. But I decided to make it for our regular dinner this week. It’s one of those versatile recipes that work just as well for special occasions as it does for a family dinner.

And that’s as it should be, yes? Because if you think about it, every family meal is a special occasion. 

What is Gratin? And What’s with the Sweet Potato?

When cooking a casserole with layered potatoes, people often use “scalloped” and “gratin” interchangeably. However, there is a difference between the two.

Scalloped potatoes are made with a cream sauce. Potato gratin (or potatoes au gratin) adds plenty of cheese to the dish, which is another way of saying they’re even more delish!

You’re probably familiar with regular scalloped or gratin potatoes, using white or yellow spuds. They’re always a family favorite and you can certainly substitute them in this recipe if you’d like.

However, using sweet potatoes in this gratin recipe gives a surprisingly tasty twist to a classic dish. Yes, they add some sweetness but just a touch! Thanks to the ham, onions, cheese and plenty of fresh thyme, the overall flavor profile for the recipe is a savory delight.

Let’s Talk Cheese

My recipe for Sweet Potato Gratin with Ham calls for two kinds of cheese – sharp cheddar and gruyere. The flavorful bite of sharp cheddar is a beautiful foil for the slightly nutty richness of the gruyere.

However, you could use just about any rich, flavorful, cow’s milk cheese in this recipe. Parmesan, grana padano, swiss, or medium cheddar would all work well. I’d stay away from mozzarella though; it’s just too mild. And blue cheese is probably too strong.

Most of the cheese gets melted into a cream sauce that you’ll make on the stovetop, but a little of the gruyere is reserved to sprinkle on top near the end of baking.

And Cheese Sauce

Making the sauce is simple. After cooking the onions, garlic, and thyme in butter, you’ll add flour and cook it for a minute or so. Then you’ll whisk in the milk and cook the sauce for a few minutes so it gets thicker. Finally, you’ll add the cheese, which will be poured over the layers of potatoes and ham.

I’m using whole milk for the cream sauce, not actual cream. You could sub cream if you want to, but I don’t think it’s necessary and it’ll save you some fat and calories. However, I’d advise against using lower fat milk in place of whole, it’s just not rich enough.

A Couple More Tips for Your Sweet Potato Gratin with Ham

Fresh thyme makes a subtle but important addition to the cream sauce, giving the dish an extra depth of flavor. It also looks really pretty sprinkled on top at the end. I really think that fresh is best here. But if you don’t have it and can’t get it, you could sub dried thyme and use half as much.

Be sure to taste the cream sauce before you pour it on the gratin. Between the salted butter, the salty ham, and the cheese, the sauce has quite a lot of salt to begin with. However, you may want to add just a touch at the end.

Also, don’t be afraid to add a generous amount of fresh ground pepper. It kicks up the savory side of this dish in a really good way. I ended up adding just a quarter teaspoon of Kosher salt to my sauce, but about three-quarters of a teaspoon of pepper.

Sweet Potato Gratin with Ham

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• Author: Marie Bostwick
• Yield: 6 servings 1x

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Ingredients

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• 2 T salted butter
• ½ sweet onion, peeled and chopped small
• 2 cloves garlic, peeled and minced
• 3 tsp fresh thyme leaves, divided
• 2 T flour
• 1.5 cups whole milk
• 1 cup extra sharp cheddar
• ½ cup gruyere, divided
• 2 lbs sweet potatoes, peeled and thinly sliced (approx. eighth of an inch)
• 1.5 cups diced ham
• Salt and pepper to taste
• Cooking spray

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Instructions

1. Preheat oven to 375 degrees. Grease an 8×8 casserole or glass baking dish with cooking spray.
2. Melt butter in a heavy bottomed pan over medium heat. Add the onions, garlic, and 2 tsp of thyme leaves. Cook, stirring frequently, for about 4-5 minutes, until onions are soft and translucent. Add flour to pot, cook and stir for one minute. Slowly pour in the milk, whisking vigorously to prevent lumps. Reduce heat to low and cook sauce for about 5 minutes, whisking frequently. Add all the sharp cheddar and half of the gruyere to the pan. Cook and stir until cheese is melted. Remove pan from heat. Taste sauce and adjust seasonings.
3. Layer half of the sliced sweet potatoes in the glass baking dish. Top with all of the diced ham. Pour half of the sauce over the sweet potatoes and ham. Layer the remaining sweet potatoes on top and pour on the rest of the sauce. Cover the baking dish with foil. Place in the preheated oven and bake for 50 minutes.
4. Remove the baking dish from the oven. Remove foil and sprinkle the remaining gruyere over the potatoes. Return pan to oven and bake for an additional 20 minutes, until the cheese is melted and the potatoes are turning golden brown. Sprinkle the remaining teaspoon of thyme over the top of the potatoes and serve.