This mashed potato gratin absolutely wowed our recipe testers who reveled in the ultra-creamy, buttery cheesiness of panko-topped mashed potatoes. Try it for your next family dinner and watch everybody swoon.
My Belgium-born mother certainly knows her way around the potato. It was a mainstay in her childhood garden and cold cellar (“kelder” in Dutch), making it a staple at most meals. She always tops creamy mounds of whipped potatoes (never made without egg yolk and nutmeg) with crispy breadcrumbs. Although she lives two hours away (three with Southern California traffic), I feel like she’s in the kitchen with me every time I make one of her recipes. This is a particular favorite, especially for entertaining, because you can get away with making it in advance and still serve warm potatoes.–Valerie Rice
Mashed Potato Gratin
- 4 (about 2 pounds) russet potatoes peeled and cut into 1-inch (25-mm) pieces
- 3 1/2 teaspoons Diamond Crystal kosher salt (or 2 teaspoons Morton kosher salt)
- 2 1/4 cups half-and-half
- 1 1/2 sticks (6 oz) unsalted butter
- 1/2 teaspoon ground white pepper
- 1/4 teaspoon freshly grated nutmeg
- 1 large egg yolk
- 1/2 cup panko bread crumbs
- 1/4 cup freshly grated Parmesan cheese
- 1 tablespoon chopped fresh parsley
- 1 tablespoon extra-virgin olive oil
- Preheat the oven to 350°F (177C).
- Place potatoes in a large pot and add 2 teaspoons salt (1 teaspoon, if using Morton) and enough cold water to cover by 2 inches (5 cm). Bring the potatoes to a boil over high heat, then reduce heat and simmer until tender, 10 to 20 minutes.
- Drain the potatoes and return to the hot pot. Place over low heat and simmer until dry, then use a potato masher to thoroughly mash the potatoes.
- In a small saucepan over medium heat, warm the half-and-half, butter, pepper, and nutmeg until the butter melts. Remove from the heat.
- Place the egg yolk in a small bowl. Ladle in a small scoop of the warm milk mixture and whisk to temper the yolk. Whisk the tempered egg yolk back into the milk mixture.
- Slowly whisk the milk mixture into the potatoes. The potato mixture will be very loose. Season with the remaining 1 1/2 teaspoons salt (1 teaspoon, if using Morton).
- Butter an 8x12-inch (20-by 30-cm) oval gratin baking dish.
- In a small bowl, combine panko, parmesan, parsley, and oil. Pour the mashed potatoes into the dish. Sprinkle with the breadcrumb mixture. (Can be made 6 hours ahead. Cover and refrigerate.)
- Bake gratin until the top is golden brown and heated through, 35 to 45 minutes. If made ahead, allow for an extra 10 minutes of cooking time.
☞TESTER TIP: If your gratin seems a little loose after baking, let it cool for a few minutes. It should firm right up.
*Why are my mashed potatoes gluey and gummy?Overworking potatoes is the number one reason for that gluey or gummy texture that we've all experienced. Potatoes are pretty much all starch, and starch doesn't like to be vigorously handled. There are a few ways to avoid this, fortunately. Always use warm liquids when mashing—it will absorb better and faster so that you don't overwork those spuds. Mash by hand or use a potato ricer. A food processor is just too much power and will lead to that dreaded potato paste.
Recipe Testers' Reviews
PURE HEAVEN. I'll never make regular mashed potatoes again. I made half the amount which should have been enough for four people, but two of us devoured the entire thing! We just couldn't stop. This mashed potato gratin is luscious and silky and the crumb topping just takes it to the next level. It's such a simple recipe, and definitely, one to make ahead for a dinner party. Your guests will love you for this one.
I served this with lamb and rapini for Easter dinner and it was a gorgeous meal.
Creamy and delicious! At first, I was concerned as the prepared mixture looked more like a thin potato soup. I ventured on, hoping it would turn into a smooth and luxurious finished product—which it did! The browned, crunchy, cheesy crumb topping complemented the taste of the smooth potatoes beneath. Not too heavy, although rich. And, plenty of leftovers for our small family of two. I served the mashed potato gratin with a hearty roast brisket, which was perfect, as the seasonings of both didn't compete with one another. Although I ended up with a sink full of dishes, I'll make it again.
Originally published May 08, 2021