Cheesy, oniony GRATIN
That brings the family together
The members of the allium family can be a confusing lot.
What is the difference between spring onions and regular onions? Is it still green garlic if it’s purple at the bottom? And why, exactly, are leeks so much grittier than their oniony cousins?
It all seems particularly perplexing in late spring, when just-plucked alliums hit the markets, arriving as verdant, more tender versions of their mature selves. This is the time to take full advantage of their youthful attractions. Treat them as vegetables rather than as seasonings, and make them the stars of the plate.
This recipe layers onions, leeks and green garlic into a cheesy, golden gratin covered with anchovy-laden bread crumbs. To accentuate the vegetables’ sweetness, brown them in butter before adding cream and cheese to the pan. More browning happens in the oven as the bread crumb and Parmesan topping toasts.
But before you head to the market, here is what to look for.
Spring onions, also called new onions, are freshly dug bulbs with taut skins, their green shoots still attached. When their skins become dry and brittle and their greens fall off, they mature into the familiar onions we find year-round. While still young, they are sugary and very juicy.
Green garlic, which can have a purple cast, is still just a child — a skinny, leggy stalk without the pungent head of its adulthood. Think of it as garlic lite, and use it raw or cooked, in salads, soups or sautés, where it adds a more delicate bite than its elders.
Spring leeks are dirty at heart, filled with more soil than other leeks because they’ve been overwintered in the field. Farmers leave them in the ground, piling on more soil to protect them from the cold. Then, they harvest the leeks in spring, when they’re sweet, richly flavored — and laced with soil. Give the leeks a thorough wash by halving them lengthwise and running them under a vigorous tap, letting the water swish away the soil trapped in their layers.
And, just to set the record straight, I’ve added another member of the allium clan to the pan: scallions, also called green onions. They are not the same thing as spring onions, but rather a lovely vegetable in their own right. (Don’t you hate it when someone confuses you with your sister?) Everything works beautifully in this bubbling gratin, where family dynamics are at their best.
Leek and Spring Onion Gratin
3 scallions, thinly sliced
2 stalks green garlic or 2 garlic cloves, thinly sliced
1⁄2 teaspoon fine sea salt, more as needed
1⁄4 teaspoon black pepper
3 leeks, white and light green parts only, halved lengthwise and cut into 1-inch pieces crosswise
2 spring onions, cut into 1-inch wedges
3 tablespoons butter, cut into cubes
5 anchovies, minced
1⁄3 cup grated Parmesan cheese
2⁄3 cup panko bread crumbs
1 teaspoon thyme leaves, finely chopped
1 teaspoon finely grated lemon zest
Pinch of red pepper flakes
1 tablespoon extra-virgin olive oil, plus more for drizzling
4 ounces Gruyère, coarsely grated
1 cup heavy cream
Place rack in the top third of oven and heat to 400 degrees. In a medium bowl, toss scallions, green garlic, salt and pepper.
Heat a 12-inch cast-iron skillet over medium heat. Arrange the leeks cut-side down in the skillet, then scatter spring onions in the gaps. Sprinkle a little more salt on top, then spread scallion mixture in an even layer in pan. Pour in 1⁄4 cup water and top with butter.
Cover and simmer on low heat until vegetables are soft, 20 to 25 minutes.
Uncover the pan, turn heat to medium-high, and cook until liquid is evaporated and edges are starting to brown and sizzle, 5 to 10 minutes longer.
Meanwhile, in a small bowl, rub together anchovies, Parmesan, panko, thyme, lemon zest, and red pepper flakes. Drizzle in oil and toss to combine.
Sprinkle Gruyère evenly into skillet over leeks, pour in cream, then top with bread-crumb mixture. Drizzle with a little more oil. Transfer to oven and bake until golden and bubbly, 15 to 20 minutes. Cool slightly, then serve warm.
Total time: 1 hour. Yield: 6 servings.