Mix slightly warm milk, lemon juice, and vanilla paste in a bowl, set them aside.
Place self raising flour, baking powder, sugar, and butter in a bowl of a food processor.
Blitz on high speed for 7-8 seconds until it resembles fine breadcrumbs.
Pour the milk mixture and currants over the flour and blitz for another 7-8 seconds until the mixture turns into a dough ball.
To make the scones traditional way without a food processor, place the flour, baking powder, butter, and sugar in a large bowl. Rub the butter in flour with your fingertips until the mixture resembles fine breadcrumbs. Pour the milk mixture into the flour mixture, add the currants, and stir gently until just combined.
Transfer the dough onto a clean surface and knead gently for a few seconds. Avoid over mixing to keep the scones tender.
Lightly dust the dough with a little flour and gently roll the dough out into a 1 inch (2½ cm) thick round.
Use a round cutter (or a glass) to cut out scones. Gather any scraps, reshape, and cut out more scones. I used 2½ inch (6½ cm) cutter and it gave me 6 scones.
Preheat the air fryer to 392°F (200°C) for a couple of minutes. Place a sheet of parchment paper in the air fryer basket.
Arrange the scones in a single layer, leaving space between them. Brush the tops with a little milk for a golden finish.
Air fry for 8-10 minutes until lightly golden and puffed up.
Transfer to a wire rack and let cool slightly before serving.