For ultimate cheesy potato gratin use a quality cheese

As the saying goes, if it’s not broken, don’t fix it.

I agree with this philosophy, but with one caveat: You can always add more cheese — especially when making a potato gratin.

A potato gratin is a cheese lover’s gift, with ultrathin layers of sliced potatoes blanketed in oozing cheese, cream and, yes, more cheese. It’s a rich and comforting side dish, guaranteed to soothe any seasonal blahs, with the promise of tipping a dinner to the luscious point of no return.

It’s important to invest in the cheese you choose for a gratin. Your cheese must easily melt, of course, and should also provide flavor to the entire dish, including hints of sharpness, earthiness and/or nuttiness. A surefire source I recommend would be the Swiss alps. Note that the term “Swiss” does not refer to the ubiquitous hole-riddled cheese you’ll find at your supermarket deli counter. Swiss, in this context, refers to the country and its mountainous alpine region.

The Swiss know their cheese, which they take very seriously; it’s designated as one of their cultural icons and is a staple in their cuisine. Consider fondue and raclette, two iconic Swiss alpine dishes that feature melted cheese. Fondue is a simmering pot of melted cheese and wine, and raclette is a melted hunk of cheese scraped and spread over cooked potatoes.

The Swiss cheese types may vary in flavor and strength depending on their age and region, but the common denominator is that they are sourced from their many happy cows (another cultural icon) that blissfully feed on the grass and fauna in the mountains and valleys, which in turn influence and flavor the cows’ milk. The result is a smattering of sublime cheeses that are sweet, nutty, floral and earthy and have a flavorful impact on a gratin (or any dish) where cheese is prominent. They are worth the splurge.

I also suggest purchasing more cheeses than you need for this recipe, because they are delicious to nosh on their own.

Swiss Potato Gratin

Yield: Serves 6

INGREDIENTS:

• Unsalted butter
• 2 cups (16 ounces) sour cream
• 1/4 cup heavy cream or half-and-half
• 3 garlic cloves, minced
• 2 teaspoons chopped fresh thyme and/or rosemary leaves
• 1/4 teaspoon ground nutmeg
• Kosher salt
• Freshly ground black pepper
• 6 ounces coarsely grated Gruyere cheese
• 6 ounces coarsely grated raclette or Appenzeller cheese
• 2 1/2 to 3 pounds Yukon gold potatoes, very thinly sliced, preferably with a mandoline

DIRECTIONS:

1. Preheat the oven to 375 degrees. Butter a 2-quart gratin or baking dish.

2. Whisk the sour cream, cream, garlic, thyme, nutmeg, 1/2 teaspoon salt and 1/4 teaspoon black pepper in a bowl. Combine the cheeses in a separate bowl.

3. Arrange half of the potatoes in an overlapping layer in the baking dish. Lightly season with salt and black pepper. Spread half of the cream mixture over the potatoes. Sprinkle half of the cheese over the cream. Arrange the remaining potatoes over the cheese and season with salt and black pepper. Top with the remaining cream and then sprinkle the cheese to cover.

4. Butter one side of a piece of aluminum foil and place the foil, butter-side down, over the dish. Bake for 1 hour. Remove the foil and bake until the top is golden brown and bubbly and the potatoes are tender when a knife is inserted, 20 to 30 minutes more. Let the gratin cool for 15 to 20 minutes to settle. Serve warm.

Lynda Balslev is an award-winning food and wine writer, cookbook author and recipe developer. She also authors the blog TasteFood, a compilation of more than 600 original recipes, photos and stories. More recipes can be found at chicago.suntimes.com/taste.