There is not much to say about them except that they are excellent, and surprisingly not that unhealthy.
I have made these a couple times now and they are always satisfyingly savory and crispy. I use a mandolin to thinly slice the onions and I use the grater plate from my food processor to grate the potatoes (which by the way is a totally awesome time saver).
Here is the recipe which I have adapted slightly.
Oven Roasted Potato or Hash Brown Cakes
1 1/4 cups paper-thin onion slices
1 1/2 – 2 pounds Russet potatoes, peeled, coarsely grated on large holes of box grater or in processor (about 3 cups)
2 teaspoons salt, divided
2 tablespoons unsalted butter, melted
Preheat oven to 425°F.
Place a Silpat or greased parchment paper on a baking sheet.
Place onions in a large bowl.
Toss potatoes with 1 teaspoon salt in medium bowl. Let stand 5 minutes. Using hands, squeeze out excess liquid from potatoes.
Add potatoes, 1 teaspoon salt, and melted butter to onions. Toss to coat.
Divide mixture into 6 mounds on prepared baking sheet, spacing apart. Roast 15 minutes, then turn mounds over with spatula, pressing down to flatten (cakes will still be soft, so just reshape them if they fall apart a little).
Reduce oven temperature to 350°F. Bake until cakes are golden and crisp around edges, about 45 minutes longer. Flip the cakes again about 15 minutes before they will be done.
As I said earlier, I use my mandolin to get thin uniform onion slices. This is not necessary and a knife will work just fine, just be sure to slice them as thinly as you can.
One of my favorite kitchen toys is the grater plate of my food processor. It grates these potatoes literally in seconds.
This is what they looked like after 15 minutes in the oven. They are flipped at this point.
These are a really great alternative to your standard pan fried potato pancake. They are nicely crisp but not overly greasy. I like to serve these with some simple pork chops and roasted apples. You could also make mini pancakes and serve them as an appetizer topped with a little smoked salmon, maybe some caviar, or perhaps a little horseradish cream. These would also be really yummy at breakfast. The possibilities are endless.