Preheat the oven to 200°C (400°F) and line a baking sheet with parchment paper. Chill your All-Butter Puff Pastry until ready to roll.
In a bowl, combine the Currants with the Light Brown Sugar, finely chopped Mixed Candied Peel, a pinch of Salt, ½ teaspoon each of Ground Allspice and Ground Nutmeg, and the zest and a little juice of one Lemon. Stir in a knob of softened Unsalted Butter until the mixture is moist and cohesive.
Roll the All-Butter Puff Pastry on a lightly floured surface to about 3–4 mm (1/8 inch) thick and cut into 10–12 circles (or use squares) — roughly 8–10 cm (3–4 in) across.
Divide the currant filling into equal portions and mound each portion in the center of half the pastry rounds, leaving a border around the edges.
Brush the edges of the filled rounds with a little beaten Egg, then top with the remaining pastry rounds and press or crimp the edges to seal. Prick the top of each cake a few times with a fork to vent steam.
Lightly brush the tops with the remaining Egg wash and sprinkle generously with Demerara Sugar for a caramelized crunch.
Arrange the cakes on the prepared baking sheet with space between them and bake at 200°C (400°F) for 18–22 minutes, or until puffed and deeply golden.
Remove from the oven and cool slightly on a rack — Eccles cakes are best served warm, letting the filling settle slightly before enjoying.
