(if not making sauce, use 2-10.75 ounce cans cream of mushroom or chicken soup).
2 tablespoons unsalted butter, plus additional for buttering the baking dish
3 green onions, finely chopped
3 cloves garlic, minced
½ teaspoon salt
8 oz sliced mushrooms (optional)
2 tablespoons AP flour
½ cup milk
2 cups heavy cream
12-ounce package elbow noodles, about 4 cups
2 5-ounce cans tuna, drained
1 tablespoon capers, drained and rinsed
¼ teaspoon red chili flakes
Zest of one lemon
2 cups panko breadcrumbs, tossed with 3 tablespoons olive oil
Chopped parsley for garnish
Preheat the oven to 375 degrees
Butter a 9x13 ovenproof casserole dish and set aside
To make the sauce: in a heavy saucepan, melt 2 tablespoons butter over medium heat.
Add green onions and garlic and cook until fragrant, about 3 minutes
Add ½ teaspoon salt and stir to combine.
Add mushrooms (if using) and cook until tender, about 5 minutes
Distribute the flour over the cooked vegetables, stirring to coat all the vegetables. Cook for about 1 minute to cook out the taste of flour.
Add the milk and heavy cream. Bring to a simmer and simmer until slightly thickened, about 5 minutes.
Taste the sauce and season with salt and pepper, if needed.
While the sauce is finishing, cook the noodles in salted, boiling water according to the package directions. You will want to cook them to the al dente directions, as they will continue to bake in the oven.
Drain the pasta and reserve ¼ cup of the cooking water
Toss the noodles with the sauce while the noodles are still hot. If the sauce looks too dry, add the reserved pasta water a little at a time until it looks creamy and delicious.
Add tuna fish, rinsed capers, chili flakes, and lemon zest to the pasta mixture and toss to combine
Place pasta mixture in the prepared baking dish
Sprinkle with breadcrumbs and bake, uncovered, until the top is golden brown and the filling is bubbly, about 30 minutes
Allow to rest 5 minutes before cutting into the casserole
Top with freshly chopped parsley and enjoy!