It is a light, flaky pastry filled with a mix of roasted, crushed hazelnuts and apricot jam.

It has an "X" (or "cross") cut into the top to allow for the food to vent hot air during baking.

Spanisch Brötli were first mentioned in a 1701 book by Samuel Hottinger about the city and baths of Baden.

This allowed Spanisch Brötli to be brought to Zürich in just 45 minutes, leading to the line being informally known as the Spanisch-Brötli-Bahn from then on.

During the 20th century these pastries fell out of favour and were almost forgotten until local bakeries revived the recipe in 2007, creating some new variants.