Stir-up Sunday is the last Sunday before Advent. The custom comes from when families & relatives gathered together and stir the ingredients of a traditional British Christmas pudding before the first Sunday in Advent as observed by Anglican churches.
There is a Collect (prayer)
‘Stir up, we beseech thee, O Lord, the wills of thy faithful people; that they, plenteously bringing forth the fruit of good works, may of thee be plenteously rewarded; through Jesus Christ our Lord. Amen.’
Also, It allows time for the pudding to mature properly for the month before the Christmas Day meal. By tradition, each member of a family or participant is encouraged to make a wish as they stir.
The pudding mixture is stirred from East to West in honour and remembrance of the three wise men who visited the baby Jesus with their gifts.
In some households, silver coins are added to the pudding mix. It is believed that finding a coin brings good luck.
I remember as a child in the 1960s, my mother would traditionally put & stir ‘silver’ sixpence coins known colloquially as a tanner into the mixture. Later when the UK went decimal ‘other’ silver coins were added.
It is believed that like Christmas trees and Christmas decorations, Christmas puddings were introduced to the UK in the 1800s, by Prince Albert, who was the husband and consort to Queen Victoria.
There can be some variations of ingredients, traditional puddings mainly contain dried fruits, raisins etc. The mixture and cake are held together by egg and suet & sometimes moistened by treacle or molasses. It is flavoured with cinnamon, nutmeg, cloves, ginger and or other spices. Measured alcohol is added, mainly brandy but dark beers or stout can be used.
Before the pudding is served during the Christmas meal, some households set light to the pudding as the alcohol content allows it to burn briefly as part of the serving tradition.
The pudding is usually aged for a month or more,[or even a year until the following Christmas Day; the high alcohol content of the pudding prevents it from spoiling during this time.