I really like Au Gratin Potatoes and my kids love it so much they ask their Grandma to make it with holiday meals. In search of something similar, but a little lighter I came up with a Sweet Potato Gratin that is simple, satisfying, lighter and more nutritious than the standard Au Gratin Potato recipes. This recipe calls for yams, which are often used in place of actual sweet potatoes in the U.S. Along the way I found myself asking what “Gratin” or “Au Gratin” even means. It is a little embarrassing that I didn’t know for certain after years of cooking and cooking classes. I had a hunch it had something to do with being covered in cheese. Here is the actual definition:
“Gratin is a widespread culinary technique in which an ingredient is topped with a browned crust, often using breadcrumbs, grated cheese, egg and/or butter. Gratin originated in French cuisine and is usually prepared in a shallow dish of some kind.” – Wikipedi
I was pretty close with my cheese theory, but now we all know what we are dealing with here. The recipe below is not weeknight quick, but can be made ahead and reheats well in the oven or microwave.
• 3 organic medium yams, sliced in thin rounds – a mandolin is great for uniformity
• 1/4 tsp each salt and freshly ground pepper
• 1 tsp thyme, roughly chopped or substitute dried
• 3/4-1 cup Parmesan cheese, finely grated (gouda or Asiago are great substitutions)
• 2 cups local milk or plain almond milk
1. Preheat the oven to 400 degrees.
2. Butter or lightly oil a baking dish or cast iron skillet.
3. Place the sliced potatoes in a bowl and season generously with salt and pepper. Add the thyme and half of the cheese and toss together.
4. Transfer to the dish and pour on the milk. It should just cover the potatoes.
5. Bake 30 minutes, remove from oven and carefully drain off a bit of the liquid. Sprinkle the remaining cheese over the top and return to the oven.
6. Bake another 45-50 minutes, until the milk is absorbed, the potatoes are soft and the top and edges are golden and around the edges.
7. Let rest at least 20 minutes before serving so the juices can redistribute.