In a mixing bowl, combine flour, sugar, and salt.
Add the cubed butter and toss to coat in flour.
Using your fingers or a pastry cutter, lightly cut the butter into the flour, leaving plenty of large chunks of butter. This is what creates flakiness.
Gradually drizzle in the ice-cold water, mixing gently until a shaggy dough forms.
Press the dough together (don't knead), wrap in plastic wrap, and freeze for 30 minutes.
On a floured surface, roll the dough into a rectangle. Fold into thirds like a letter.
Turn, roll again, fold into thirds, then freeze for 30 minutes.
Repeat this process (rolling, folding, chilling) two more times. This builds flaky layers.
In a small bowl, mix currants, sugar, and cinnamon until well combined.
Roll the dough into a rectangle, about ¼-inch thick.
Evenly spread the currant mixture over the surface.
Roll up the dough tightly, starting from the long side, then pinch the seams to seal.
Place on a lined baking sheet. Brush the top with egg wash.
Bake at 375°F for 30–35 minutes, until golden brown.
Allow to cool before slicing into pieces.
