- 1 tablespoon butter
- 3 large leeks, white and light green parts only, cleaned and thinly sliced
- 2 ½ to 3 pounds Idaho® potatoes, peeled and sliced as thinly as you can manage
- 2 cups half-and-half
- 1 cup crumbled blue cheese (about 1/3 pound)
- Kosher salt and freshly ground black pepper to taste
- Preheat the oven to 350° F.
- In a large skillet melt the butter over medium heat. Add the leeks and saute for 8 to 10 minutes until they are tender.
- Layer half the potato slices evenly in a 9 x 13-inch pan, and spread over half of the leeks. Pour over half of the half–and-half, sprinkle over half of the cheese. Season with salt and pepper. Repeat the layers.
- Bake uncovered for 1 hour and 15 minutes, until the top is golden brown (cover the pan with foil if the top gets starts too brown too early) and when a knife inserted into the middle glides easily through the potato layers.
- Let the gratin sit on a wire rack for about 15 minutes until the cream has a chance to set up a bit, and absorb into the potatoes. Serve hot or warm.
- The Skinny on Mandolins:
- You should be able to read the paper through that potato slice!
- Okay, that’s asking a lot, but you do want to take the time to make the slices of potato as thin as possible. This can certainly be achieved with a cutting board and a sturdy knife but if you’re going to make a habit of thinly slicing things, you may want to invest in a mandolin, an apparatus that allows you to slide produce and other foods across a blade and get even, super delicate slices (or thicker slices; the blade is adjustable).
- Conversations about mandolins usually go something like this: There are excellent pricy ones (a varied bunch of them, with some fancy attachments), but chefs and avid home cooks alike praise the Berniner as a very efficient and effective cheap mandolin, also with an adjustable knob. Start with that, and if you get addicted to thinly slicing things, and feel like you want more, treat yourself to a fancy one.
- And it just needs to be said: be careful, pay attention, and never look away when you are slicing.
Make Ahead: This can be made a day ahead of time and reheated, uncovered, in a 350° F oven for 20 minutes. Microwaved squares of gratin are also a great treat the next day.