For the vegetable casserole, boil the potatoes, peel and slice them. Meanwhile, cook the pasta in salted water until al dente. Put the potatoes in a baking dish on the bottom and on the edge.
Put the pasta and the vegetables (can be frozen) on top. Pour hollandaise sauce over the whole and cover with potatoes.
Put the bacon pieces on top. Bake the vegetable casserole at 200 °C for half an hour until golden brown.