Step 1
Preheat oven to 400°. Grease a 13×9″ baking dish with 1 Tbsp. unsalted butter.
Step 2
Cook 12 oz. dried curly egg noodles in a large pot of boiling salted water, stirring occasionally, until very al dente, about 2 minutes. Drain pasta; let cool.
Step 3
Melt 4 Tbsp. unsalted butter in a large skillet over medium heat. Add 1 large onion, finely chopped, and 1 medium leek, white and pale green parts only, finely chopped; cook, stirring, until soft but not brown, 8–10 minutes. Increase heat to medium-high and add 10 oz. mushrooms (such as crimini, shiitake, and/or button mushrooms), chopped. Cook, tossing occasionally, until most of the mushroom liquid has evaporated, 4–6 minutes. Add ¼ cup white wine and reduce until skillet is almost dry, about 2 minutes; season with kosher salt and freshly ground black pepper. Stir in 1 Tbsp. Worcestershire sauce and 2 tsp. finely chopped thyme.
Step 4
Melt remaining 4 Tbsp. unsalted butter in a medium pot over medium-low heat. Whisk in ¼ cup (31 g) all-purpose flour and cook until roux is golden and looks shiny and smooth, about 2 minutes. Whisking constantly, add 2½ cups homemade chicken stock or low-sodium chicken broth and bring to a boil. Reduce heat to medium and add 1 cup heavy cream, 6 oz. white cheddar, grated, and 2 tsp. hot sauce; cook, stirring, until cheese is melted, about 1 minute. Season with salt and pepper.
Step 5
Gently fold mushroom mixture, cream mixture, cooked noodles, and two 6-oz. jars oil-packed tuna, drained, broken into small pieces, in a large bowl; taste and adjust seasonings if needed.
Step 6
Transfer tuna mixture to prepared baking dish. Press 2 cups potato chips into casserole so they stand upright. Bake casserole until bubbly around the edges and chips begin to brown, 15–20 minutes. Zest one quarter of 1 lemon over casserole. Let sit 5 minutes, then top with ½ cup dill, coarsely chopped, and 2 Tbsp. finely chopped chives.
Editor’s note: This recipe was originally published in February 2016 as part of BA’s Best, a collection of our essential recipes. Head this way for more of our best casserole recipes →