Liebesapfel refers to one of the sweet treats (Süßegkeit) available in Germany during festival seasons , partcularly available for sale during Carnivals, very popular in Christmas Night markets (Weinachtsmarkt) and other occassions open to the general public, like in Bremen's Ischa Freimarkt, an almost 990 year old festival every autumn.
Liebesapfel translated in English as "Love Apple" is actually a sugar-coated apple in red color so it will still appear like a fresh apple with a stick handle. Moreover, it is an apple candy made from fresh apple coated in red colored sugar.
In North America , Liebesapfel is known as Candy apple and in France, it is called Pommes d'Amour (Apples of Love)
The picture below is from the Weinachtsmarkt (Christmas Market) in Bremen.
List of books: Liebesapfel