Preheat your oven to 180C and line two baking trays with baking paper. Remove puff pastry from the freezer and defrost for ten minutes on the bench
Brush each sheet of pastry with the egg wash, before sprinkling one sheet evenly with the fennel seeds, rosemary and a few good cranks of black pepper
Scatter your Gruyère all over the same sheet of pastry, reserving a small amount for the next step
Layer the remaining sheet of pastry on top and press firmly to stick together. Brush with more egg wash and slice lengthwise into fifteen strips
One by one, transfer the strips to the baking trays, twisting a few times as you go. Sprinkle the reserved Gruyère on top and bake for 25 mins or until golden
