Step 1

Arrange a rack in the middle of the oven and heat to 400°F. Lightly coat a 2-quart or 9x13-inch baking dish with oil; set aside.

Step 2

Bring a large pot of salted water to a boil. Add the noodles and cook for 2 minutes less than recommended on the package directions. Drain the noodles, then transfer them to a large bowl. Toss them immediately with a drizzle of olive oil so they don't clump together; set aside.

Step 3

Fill the pot with water again and bring to a boil. Add the potato slices and cook for 4 minutes. Drain well, then return them to the pot.

Step 4

While the noodles and potatoes are cooking, heat the butter in a small saucepan over medium heat. When it melts and foams up, add the flour and cook, stirring frequently, for about 5 minutes. Whisk in the milk. Cook, stirring constantly, until the sauce thickens slightly, about 5 minutes. Stir in 1 teaspoon of the salt and pepper to taste.

Step 5

Add the egg noodles to the pot of potatoes, then pour the sauce over them. Stir in the remaining 1 teaspoon salt, tuna, artichoke hearts, capers, olives, scallions, parsley, and 1/2 cup of the Parmesan cheese. Taste and season with more salt as needed.

Step 6

Transfer to the baking dish and spread into an even layer. Sprinkle with the remaining 1/4 cup Parmesan cheese. Bake, uncovered, until bubbly, about 25 minutes. Serve warm.