In an evening when relatively few questions seemed to pose too much difficulty to many teams, this one hid its mundane answer behind an almost wilfully obscure question.
'Rocher' is simply French for 'rock'; there's no real clue to that in the question (unless you happen to be an habitué of Lourdes – or of course unless you've heard it before).
It might have been more helpful if the question had mentioned nuts, which are an essential part of the Ferrero Rocher 'experience'.
And finally, several people I know would argue with the use of the word 'treat', which would completely throw them off the scent.
Having said all that, it does appear that the Ferrero Rocher is indeed named after its creator and the grotto at Lourdes where the Virgin Mary is said to have appeared to St. Bernadette. It was introduced in 1982 by the Italian chocolatier Michele Ferrero, whose other products include Nutella, Kinder treats and Tic Tacs. Ferrero is said to have beeen a devout Catholic, known for his strong devotion to 'Our Lady'. On the 50th anniversary of the founding of his company, he said: "The success of Ferrero we owe to Our Lady of Lourdes; without her we can do little." He was said to have made an annual pilgrimage to Lourdes, taking his top manager. He also organized a visit to the shrine for his employees, and had a statue of the Virgin Mary placed in each of his company's fourteen production facilities around the world. He died on St. Valentine's Day in 2015, at the age of 89.
The grotto is known as the Rocher de Massabielle. Senor Ferrero presumably chose to use the prosaic word 'Rocher' rather than the more exotic–sounding 'Massabielle' because of its pronouncability.
Most of the information in this note comes from Aleteia.org – a site that "offers a Christian vision of the world by providing general and religious content that is free from ideological influences." It was cited by Wikipedia.
© Macclesfield Quiz League 2019