Place the cookie balls onto the baking tray and use your knuckle or finger to press an indent into the mixture (not the whole way through!).
These biscuits are meant to be flat (they won't rise very much due to the small amount of baking powder used). If you'd like them to be slightly less flat, you can try chilling the dough in the fridge before cooking. Also, roll the dough into balls and then very gently use your knuckle to create a very small indent for the jam (don't flatten the cookie dough). Finally, you can increase the amount of baking powder to 1 tsp.