La Castañada is usually celebrated on All Saints Eve, which is the 31st October. The origins of ‘All Saints day’ or ‘All Hallows day’ come from an old festival of the dead. La Castañada is a tradition where people used to go to the cemetery to commemorate those who had passed on. They would eat foods in abundance at this time of year. Since the ritual is in autumn (which used to be much colder) the foods were calorific, foods which could sustain you throughout the winter.
Boniatos are baked sweet potatoes.
Castañas are roasted chestnuts.
Panellets are small, sweet balls of marzipan rolled in pine nuts.
These are pretty expensive now, often around 45€ per kg (because the almond powder and pine nuts are dear). To make panellets you dissolve sugar in water, combine with egg white and almond powder until you have a dough. This should be divided up into small balls, which are covered in egg yolk and rolled the topping. Traditionally pine nuts or almonds were used on the outside, more recently you also see coconut, coffee, chocolate and cherries.
This food was all traditionally washed down with Moscatel which is a sweet wine.
All over the city of Barcelona towards the end of October, street vendors pop up, selling their baked goods. If you are here at this time of the year you should try some of these foods, they mark an important tradition on the gastronomic calendar.
Haloween is now popular all over the world, but La Castañada has been an important festival here in Catalonia since long before this modern celebration. 
