Cook the noodles in a large pot of salted boiling water according to package directions, just until al dente (about 5-6 minutes). Drain.
In a large bowl, whisk together condensed soup and milk. Gently stir in the cooked noodles, tuna and peas (if using). Taste and season with salt and pepper, if necessary. Transfer mixture to prepared dish.
Sprinkle cheese on top, then crushed potato chips.
Bake for 20-25 minutes, or until top is golden brown and inside is hot and bubbly.
Cook the pasta just until al dente (tender, but with a firm bite). The noodles will continue cooking in the oven, so you don’t want them to be mushy or overdone.
Use solid white albacore tuna in water (not chunk light or other varieties).
Drain the tuna fish really well before adding it to the casserole.
There’sno need to thaw the peas before adding them to the dish. Just stir them in while they’re still frozen — this will help them stay nice and green in the casserole (rather than turning brown and mushy).
Taste the filling before baking, and season with kosher salt and freshly ground black pepper, if necessary.
A splash of sherry in the filling adds another layer of delicious flavor!