Potato and Onion Gratin with Allioli
This is from "The New Spanish Table" cookbook, which is quickly moving on to my all time favorite cookbook list.
Potato and Onion Gratin with Allioli
(Patatas Panaderas Con Allioli)
The New Spanish Table by Anya Von Bremzen
You don’t have to be Catalan to agree that pretty much everything tastes better with allioli, the bold garlic mayonnaise that brings to life so many of the region’s dishes. Patatas panaderas (the classic Spanish baked sliced potatoes) are great on their own. But add a cup of allioli and you’ve got a treat. Serve the potatoes with simple roasts that could use a garlicky kick or with saucy dishes.
3 tablespoons extra-virgin olive oil, plus more for oiling the pan
2 medium-size onions, cut in half and thinly sliced
3 pounds baking potatoes of uniform size, peeled, rinsed, and patted dry
Coarse salt (kosher or sea) and freshly grated ground pepper
¾ cup chicken stock or broth
About 1 ½ cups Allioli
1. Heat the olive oil in a large skillet over medium heat. Add the onions and cook, stirring until softened and lightly browned, 10 to 12 minutes, adjusting the heat as necessary.
2. Using a mandolin, the slicing disc of a food processor, or a sharp knife, slice the potatoes into 1/8-inch-thick rounds.
3. Preheat the oven to 375 degrees F.
4. Generously oil a heavy, shallow 12- by 9-inch baking dish, preferably earthenware or cast-enamel or an oval gratin dish (you can also use a cast-iron skillet.) Arrange some of the potatoes in one overlapping layer on the bottom of the baking dish, then season them generously with salt and pepper. Scatter half the cooked onions on top. Arrange another layer of potatoes on top of the onions, season them with salt and pepper. Scatter the remaining onions over the potatoes and top with another layer or potatoes (you might not need all of the potato slices). Press the layers down to compact them. Pour the stock over the potatoes.
5. Cover the baking dish with aluminium foil and bake the potatoes until the feel tender when pierced with a knife, about 50 minutes. Uncover the baking dish, brush some olive oil on the potatoes and bake for another 10 to 15 minutes.
6. Change the oven setting to broil. Being careful not to burn yourself, remove the baking dish from the oven and spread the allioli generously over the opt. Broil until the top is browned in spots, 2 to 3 minutes. Let cool for a few minutes, cut into squares and serve. Serves 6 to 8.
Variation: Potato gratins lend themselves to many variations. Instead of the allioli, you can top the gratin with Cabreles cheese, as might be done in Asturias. You can add sautéed bell peppers or Italian frying peppers and some chopped tomatoes or sautéed wild mushrooms to the layers of sautéed onions. Brushing the potato layers with a little saffron-infused oil is nice too.
Basic One-cup Allioli
2/3 cup extra-virgin olive oil
1/3 cup peanut or canola oil
4 large garlic cloves, minced
2 large egg yolks
4 teaspoons fresh lemon juice, or to taste
Coarse salt (kosher or sea)
Stir together both oils in a measuring cup with a spout. Place the garlic, egg yolks, and lemon juice in a blender and pulse until a coarse paste forms. With the motor running, add the oil in a slow, steady stream. The mixture will be the consistency of a thick mayonnaise. Scrape the allioli into a bowl, and season with salt to taste, and more lemon if desired. Let stand for at least 1 hour before serving, or cover and refrigerate if keeping longer. If the allioli seems too thick, thin it out with a little water before using. Makes just over 1 cup.
Variations:
Roasted Garlic Allioli
Cut off the top ½ inch from 1 medium-sized head of garlic, exposing the cloves. Place the garlic cut side up in a small baking dish with olive oil. Cover the dish with aluminum foil and bake the garlic at 375 degrees F until tender, about 45 minutes. Cool, then squeeze the cloves from their skins. Substitute for fresh garlic in Basic One-Cup Allioli. Serve with paellas, fritters, or potato tortilla.