To usher in the earliest days of spring, dig into a dish of this zippy mac and cheese spin-off. Leeks are sturdy enough to survive winter frosts, sprouting with a gradation of green colors and a mellow flavor all their own. Here, they’re slant-sliced into planks and baked with oversized noodles, all draped in a sharp cheddar sauce with a mustardy kick. Conchiglioni, a larger shell pasta, manages to nail the best of both texture worlds, staying tender when submerged and catching color and crispiness at the surface. Often stuffed with meat or cheese, they can hold plenty of sauce and even a hefty leek. Make sure to separate any stuck-together noodles before baking—they love to snuggle like nesting dolls.
Test Kitchen Tip: Look for leeks about 1½" in diameter, as opposed to thicker stalks. Leeks grow in sandy soil and can be challenging to clean, especially when large. Remove the loose outer layers, then rinse well. Trim off roots and deep green tops and place in a bowl of cold water. Let soak, encouraging sand and soil to sink, before removing.
Recipe information
Total Time
1 hour 10 minutes
Yield
4 servings
Ingredients
Preparation
Step 1
Place a rack in middle of oven and preheat to 425°. Cook 8 small leeks (about 2 lb.), white and pale green parts only, in a large pot of boiling salted water until a paring knife slides into them with just a little resistance, 9–12 minutes (parboiling the leeks should remove any lingering dirt). Using a spider or slotted spoon, transfer leeks to a cutting board and let sit until cool enough to handle. Slice crosswise on a diagonal 1½" thick and set aside.
Step 2
Meanwhile, cook 12 oz. large short pasta (such as conchiglioni or paccheri) in another large pot of boiling salted water (or, use the same pot with fresh salted water) until very al dente, about 2 minutes less than package directions. Drain pasta in a colander, reserving 2 cups pasta cooking liquid, and immediately drizzle 1 Tbsp. heavy cream over; toss to coat. Reserve pasta pot.
Step 3
Toss 8 oz. sharp white cheddar, coarsely grated (about 2 cups), and 2 tsp. cornstarch in a medium bowl; set aside.
Step 4
Bring 1 cup dry white wine to a simmer in reserved pot over medium-high heat; cook until reduced by half, about 4 minutes. Reduce heat to medium and whisk in 3 Tbsp. Dijon mustard, 1½ tsp. freshly ground pepper, remaining ¾ cup plus 3 Tbsp. heavy cream, and 1½ cups pasta cooking liquid. Add cheese mixture a handful at a time, whisking until melted and sauce is smooth after each addition. Remove sauce from heat and mix in 2 garlic cloves, finely grated, and pasta, then gently fold in reserved leeks. Season with salt and more pepper if needed.
Step 5
Transfer pasta to a 2½–3-qt. baking dish and bake until warmed through, bubbling, and deeply browned in spots, 25–30 minutes. Let cool 10 minutes before serving.
