Another interesting variation of the croissant is a lye / pretzel croissant. If used as a savoury item, adjustments to the recipe can be made by reducing the sugar levels in the recipe by 80%. Lye is also known as Sodium Hydroxide (NaOH) and as a baking application is used to produce pretzels and lye rolls. Lye products are popular in Germany and across Europe. Lye croissants are another variant which may be explored as an option for a different pastry by bakers already using lye.
The croissant is processed in the usual manner; and when ¾ proofed, the croissants are placed into a freezer, or a blast chiller for 10−15 minutes until the outside is frozen solid and the product can be handled without collapsing. A 1:10 solution of reduced food-grade lye or NaOH is prepared while the croissants are in the freezer.
Using proper safety equipment – to include safety goggles, plastic bib apron, and elbow-length rubber gloves – the frozen croissants are dipped into the lye, allowed to drip on a wire tray, before being placed onto baking sheets lined with baking parchment. The croissants should be sprinkled with rock salt, or shaved salt to distinguish them from other products. The lye croissants are then baked as normal, and the baking process removes the harmful lye through a chemical reaction between the heat of the oven and the NaOH. Lye croissants have a rich chestnut colour, exposing the paler white layers of pastry in contrast to the accelerated Maillard reaction of the lye on the outer skin. They are attractive to look at and make beautiful savoury canapes.
Full recipe and more tips are available in my book, The Art of Lamination: Advanced Technical Laminated Pastry Production.