Rolling Craquelin Thin for Lift

Craquelin is there for crackle and an even rise, not for substance. Rolled thick it becomes a lid the choux has to lift, which weighs the buns down and flattens them. Beat softened butter with brown sugar, work in flour, ground almonds and a pinch of salt to a smooth paste, then roll it between two sheets of parchment to just 1.5 to 2 mm. 

Freeze the sheet until firm, cut discs a touch smaller than the piped rounds, and set them on frozen, straight from the freezer. 

Thin and cold, the craquelin shatters into a fine craze and lets the choux do the rising.