Preheat oven to 500°F. Line a baking sheet with parchment paper.
In a food processor, pulse flour, sugar, baking powder and salt until combined.
Add the softened butter and pulse till fully incorporated and the mixture resembles very fine crumbs, about 20 seconds. Transfer this mixture to a mixing bowl and stir in the currants.
In a measuring cup, whisk milk and egg replacer mixture together. Set aside 2 tbsp of this mixture. Add the rest to the flour mixture and mix until there are no dry bits of flour in the bowl.
Transfer the dough to a well floured surface and gather into a ball. With floured hands, knead until the dough is smooth with no cracks. Press into a disk and roll it out using a floured pin into a 9" round disk, about 1" in thickness.
Cut the scones out using a floured 2½" round biscuit cutter. Arrange the scones on the prepared baking pan. Gather the dough scraps and form into a ball, knead gently, roll out more scones. You should be able to get about 12~14 scones out of this dough.
Brush the tops of the scones with the reserved milk-egg replacer mixture.
Reduce the oven temperature to 425°F and bake the scones until risen and golden brown, about 10~12 minutes, rotating the baking sheet half-way through baking. Transfer the scones to a wire rack and let cool for at least 10 minutes. Serve warm or at room temperature.