This flavor-packed casserole is filled with egg noodles, creamy tonnato sauce, pimientos, and peas, and topped with crunchy potato chips.
1 (12-ounce) package wide egg noodles
1/2 cup mayonnaise
2 teaspoons grated lemon zest
1/4 cup fresh lemon juice
1/4 cup water
2 tablespoons drained capers
1 teaspoon black pepper
4 garlic cloves smashed
3 oil-packed anchovy fillets, drained
4 (5-ounce) cans tuna in water, drained and broken into large flakes, divided
3 tablespoons unsalted butter
1 yellow onion, finely chopped
1/4 cup all-purpose flour
1 cup half-and-half
1 cup chicken stock
4 ounces grated Parmesan cheese (about 1 cup), divided
1 cup fresh or frozen sweet peas
2 (4-ounce) jars diced pimientos, drained
1 1/2 teaspoons kosher salt
3 tablespoons chopped fresh dill, divided
2 cups potato chips
Preheat oven to 400°F. Bring a large pot of salted water to a boil over high. Cook egg noodles, stirring occasionally, until al dente, about 5 minutes; drain and rinse with cold water. Set aside.
Combine mayonnaise, lemon zest and juice, 1/4 cup water, capers, black pepper, garlic, anchovies, and 2 cans tuna in a blender; process until smooth, about 25 seconds. Set tonnato sauce aside.
Melt butter in a large Dutch oven over medium. Add onion; cook, stirring often, until softened, about 4 minutes. Sprinkle with flour; cook, stirring constantly, 1 minute. Stir in half-and-half; cook, stirring constantly, until thickened, 30 seconds to 1 minute. Stir in tonnato sauce, stock, and 3/4 cup Parmesan. Remove from heat; stir in egg noodles, peas, pimientos, salt, 2 tablespoons dill, and remaining 2 cans tuna. Transfer mixture to a 3-quart baking dish (such as a 9- x 13-inch dish).
Top casserole evenly with potato chips and remaining 1/4 cup Parmesan. Cover dish tightly with aluminum foil, and bake in preheated oven for 15 minutes. Uncover, and continue baking until heated through, about 10 minutes. Garnish with remaining 1 tablespoon dill.
