Cream together the butter, sugar and vanilla. Add in the egg and mix until well combined. Gradually add sifted flour and baking powder and mix until a dough forms.
If you have a thermomix then process the butter, sugar and vanilla on speed 5 for 20-30 seconds and scrape down the bowl. Add the egg and process 20 seconds speed 4. Add in flour and baking powder and process for about 30-40 seconds on speed 3 until a dough forms.
Place small teaspoonfuls of mixture in round balls on lined baking trays.
Press down gently with a thumbprint and place a small amount of jam in that indent.
Don't go crazy with the jam.
Bake in a preheated 160 degree oven for about 15 minutes and don't overcook the biscuit or the jam will change appearance.
Remove from oven, leave to cool a couple of minutes on the tray before moving to a cooling rack. I like to add in a dash more jam to each biscuit at this point and it makes them look a bit prettier.
Eat and enjoy.
Recipe by Retro Mummy at https://retromummy.com/2013/06/26/you-cant-beat-old-favourites-like-jam-drops/