In a large mixing bowl, whisk the flour, baking powder, salt and sugar.
Add the margarine. Cut and fold the margarine with a butter knife into the flour. Then rub the margarine into the flour with your fingertips until the mixture resembles a course sand.
Now add the non-dairy milk and the vanilla extract. Mix with your hand into a dough. The dough should be slightly crumbly, dry and non-sticky.
If the dough doesn’t hold together, add just a little more milk (a teaspoon or two) but not too much.
Place the dough in a container and refrigerate for 30 minutes or freeze for about 10 minutes. This will make it easier to roll out and you’ll also get a nicer texture.
Meanwhile preheat the oven at 180 C or 350 F.
Remove the dough from the refrigerator and place it on a large piece of parchment paper, lightly floured.
Using a floured rolling pin, roll out the dough to about 5 mm (¼ inch) thick and keep it as much as possible into a rectangular shape.
Sprinkle the currants over half of the surface of the rolled dough. Spread out evenly.
Carefully fold the other half of dough over to sandwich the raisins. Roll onto the parchment paper and gently press onto the currants while spreading and thinning out the dough a little more.
Transfer the dough together with the sheet of parchment paper onto a baking tray.
Using a long sharp knife, score the dough into strips of 4 cm X 7 cm (1½ inch x 2¾ inch). Only score the knife less than halfway through the dough so that after they are baked, they will still be connected and you can break the biscuits apart.
For the glazing, mix the non-dairy milk and the maple syrup or sugar together, then brush on the dough.
Bake for 15 minutes until the cookies are golden brown. Check after 10 minutes and keep an eye on them to make sure they are not burning.
If the top isn’t golden enough, you may broil the cookies for the last 3 minutes of the baking. But if you do this, I suggest you stand there watching as they can burn pretty quickly while broiling.
After 15 minutes, remove the cookies from the oven and allow them to cool. They will be soft when hot and will become crunchy upon cooling.