Blend flour, baking powder, salt, butter, and egg yolks in a food processor until crumbly.
Add water gradually while processing until a dough forms.
Wrap dough in film and chill for one hour.
Preheat oven to 180°C.
Toss chopped beef with flour, salt, and pepper in a bowl.
Season all chopped vegetables with salt and pepper.
Divide chilled pastry into six pieces and roll each onto a floured surface.
Trim each pastry piece into a disc using a dinner plate.
Place a layer of potato on one half of each disc, leaving a 1.5cm border.
Layer swede, then onion, then beef on top of the potatoes.
Brush the pastry edges with beaten egg.
Fold the pastry over the filling and seal the edges with a fork.
Glaze the tops with egg and cut a small steam cross in each.
Bake on a tray for 45-50 minutes until golden-brown and piping hot.
Rest for 5-10 minutes before serving.