Simnel Cake is a fruitcake that has origins in the United Kingdom and Ireland. It is also made in countries that have histories of migration from those places, such as Canada.
The cake is traditionally made either for the Fourth Sunday in Lent—coming up on 27 March this year—or Easter Day. It is characterized by alternating layers of fruitcake and almond paste or marzipan. Simnel cake is usually decorated with eleven balls of the same paste or marzipan placed on top - one for each disciple, less Judas Iscariot.
The cake is sweet and calorie-dense and was made to celebrate the loosening of the Lenten fast. The Fourth Sunday in Lent, when the Western church still held things to their Latin names, is called "Laetare" or "Rejoice". Lenten restrictions on rich foods were released on this day and people celebrated by traveling to visit their families in their hometowns and home parishes, giving rise to the tradition of this day being "Mothering Sunday".
If you'd like to bake your own simnel cake this year, there is a recipe attached to this post.