"Il menù è caro."
Traduzione:Das Menü ist teuer.
Native speaker here. "Menü" and "Speisekarte" can mean both the same, when they're used to describe a list with all possible dishes one can order. But "Menü" can also mean a fixed set of dishes with multiple courses, like appetizer, soup, main dish, and dessert. In this context "Speisekarte" is wrong.