Step 1

Bring a large pot of lightly salted water to a boil. Cook spaghetti in the boiling water, stirring occasionally, until tender yet firm to the bite, about 12 minutes. Drain thoroughly.

Step 2

Preheat the oven to 350 degrees F (175 degrees C). Thoroughly butter a 9x13-inch baking pan.

Step 3

Layer 1/2 the cooked spaghetti into the bottom of the prepared pan. Sprinkle 1/2 the cracker crumbs, 1/2 the Parmesan cheese, 1/2 the parsley, 1/2 the minced onion, and 1/2 the garlic salt on top. Pour in 1/2 of the melted butter. Repeat with remaining spaghetti, cracker crumbs, Parmesan cheese, parsley, minced onion, garlic salt, and butter.

Step 4

Mix milk and eggs together in a bowl. Pour over the spaghetti mixture.

Step 5

Bake in the preheated oven until set, about 30 minutes. Cut pie in squares.