Put oven rack in middle position and preheat to 350°F. Butter a 13- by 9- by 2-inch glass or ceramic baking dish. Cook noodles in a 6- to 8-quart pot of boiling salted water until al dente. Drain well in a colander, then return to warm pot and add butter, tossing until noodles are coated. Whisk together milk, eggs, sugar, vanilla, and salt until combined, then whisk in sour cream. Stir in cottage cheese and pineapple and add to noodles, stirring to coat well, then spoon into baking dish. Stir together cornflakes, sugar, and cinnamon and sprinkle evenly over noodles. Dot with butter and bake until kugel is set and edges are golden brown, about 1 hour. Let stand 5 minutes before serving.