Step 1

Place an oven rack in the middle position. Preheat the oven to 375 degrees F.

Step 2

Bring a pot of water to a boil over high heat. Season the water with salt and then add the egg noodles. Cook the noodles for 2 to 3 minutes short of the package instructions. Drain in a colander and set aside. Wipe the pot dry and return to the stovetop.

Step 3

Put the crumbled crackers in a medium bowl. Drizzle with the 2 tablespoons of melted butter and toss to coat the crackers in the butter. Set aside.

Step 4

Melt the remaining 4 tablespoons of butter in a large Dutch oven over medium heat. Add the carrots, celery and leeks. Cook, stirring occasionally, until wilted, 4 to 5 minutes. Add the garlic. Stir in the thyme and sprinkle with the flour. Stir to coat the vegetables in the flour and toast for 1 to 2 minutes to remove the raw flour taste. Add the nutmeg and cook for 30 seconds to 1 minute until fragrant. Deglaze the pan with the white wine. Bring to a boil and reduce to a simmer, scraping the bottom of the pot with a wooden spoon to incorporate any flavorful brown bits. Simmer for 5 minutes. Add the chicken broth and heavy cream, stirring to fully incorporate. Bring back to a boil, reduce to a simmer and season with kosher salt and several grinds of black pepper. Simmer until slightly thickened, 3 to 4 minutes. Stir in the chicken, noodles and peas. Return to a simmer for a minute to combine the flavors and then remove from the heat. Stir in the parsley, dill, lemon zest and juice. Taste and season with salt and pepper, if needed.

Step 5

Transfer the mixture into a 9-by-13-inch baking dish.

Step 6

Sprinkle with the buttered cracker crumbs. Bake until the crumbs are golden and crispy and the edges of the casserole are bubbly, about 25 minutes. Let the casserole sit for 5 minutes before serving. Garnish with parsley and dill. Serve hot.

Step 7

Leftover casserole will keep for up to 3 days, covered, in the fridge.