Eating rusk after the birth of a baby in The Netherlands

In the Netherlands, it is a custom at the birth of a baby to eat muisjes on top of rusk–beschuit met muisjes; the anise in the muisjes was thought to stimulate lactation, and they symbolized fertility.

As early as the 17th century, the parents of a newborn baby gave away beschuit with a layer of butter and muisjes to the baby’s visitors. This tradition continues today. Beschuit met muisjes are given to the baby’s visitors at home, and are brought by older siblings to share at school; or are presented to colleagues at work. Every supermarket in the Netherlands sells boxes of muisjes. “De Ruijter” is currently the only brand in production of muisjes. They have been making them since 1860.

Before the 20th century, visitors to a newborn baby got only white muisjes, then this changed to a mix of pink and white muisjes for girls and blue and white muisjes for boys.
Gestampte muisjes (“crushed muisjes”) are muisjes crushed to powder, which are sprinkled onto a slice of bread or a Dutch rusk over butter, a customary breakfast food for Dutch children.

Source: Wikipedia