Sift the flour, baking powder and salt into a large bowl.
Add the cheese, tomatoes, ham and onions and mix thoroughly.
Stir in the milk using a knife and scraping from the outside of the bowl until the ingredients are fully mixed to a soft dough. The mixture should be wet to the touch but not sticky.
Turn onto a floured surface and roll or pat out to 2cm thickness and cut into desired size and shape
Place on a greased baking tray and bake in the middle of the oven at 220°C for 10 minutes.
Reverse tray and bake for another 10 minutes.