Preheat Oven: Preheat the oven to 180ºC 356ºF (180ºC). Line a large baking sheet with parchment paper and set aside.
Mix Dry Ingredients: In a high-speed food processor, add flour, sugar, and baking powder. Pulse a couple of times to blend together.
Incorporate Butter: Add chilled, cubed butter. Pulse for 15 seconds until the mixture resembles coarse crumbs.
Add Milk Gradually: Through the vertical shoot, drizzle the milk a tablespoon at a time then pulse the mixture. Once all six tablespoons of milk have been added, continue pulsing until it begins to form a rough dough.
Form the Dough: Turn the dough onto a lightly floured surface. Gently knead and press into a rough, thick rectangle.
Prepare for Rolling: Sprinkle flour under the dough and on the rolling pin to prevent sticking.
Roll Out Dough: Roll the dough into a large rectangle, about 4mm thick, measuring approximately 40cm by 30cm (15 inches by 11 inches).
Add Currants and Chocolate: Evenly spread currants and chocolate chips over one half of the dough, then fold the other half over, matching edges carefully.
Second Rolling: Flour the surface again. Roll the dough out once more to about 35cm by 25cm (13 inches by 9 inches) and 4mm thick.
Prick Dough: Take a fork and lightly prick the dough all over, the fork shouldn’t go completely through the dough, just prick the surface.
Trim: Using a long, sharp knife, trim the edges to form a neat rectangle.
Cut in Half: Using the sharp knife, slice the dough down the middle lengthwise.
Slice into Biscuits: Cut the dough into long biscuits measuring about 10cm by 4cm (4 inches by 1.5 inches).
Arrange on Tray: Transfer the biscuits to the lined baking tray, leaving a small gap between each to allow for spreading.