Preheat oven to 180°C/160°C fan-forced. Grease 2 baking trays. Line with baking paper.
Using an electric mixer, beat butter, sugar and vanilla until light and fluffy. Add flour. Beat to combine.
Roll 1 level tablespoon of mixture into a ball. Repeat with remaining mixture to make 18 balls. Place balls, 4cm apart, on trays. Using the palm of your hand, flatten each ball slightly. Shape edges to remove any cracks.
Make an indentation in the centre of each biscuit. Fill each indentation with 1/4 teaspoon jam.
Bake for 12 to 15 minutes, swapping trays halfway, or until light golden. Cool biscuits on trays for 15 minutes. Transfer to wire racks to cool completely. Serve.