• Preheat oven to 180°C / 350°F (160°C fan-forced). Grease and line two baking trays with parchment paper, and set aside.
• Place the softened butter in a large bowl and add the sugar. Beat the butter and sugar till light and fluffy.
• Add the egg and beat for another 30 seconds – 1 minute, till combined.
• Add the cardamom powder, followed by the vanilla essence, and combine.
• Add the plain flour, and beat on low speed to combine. The dough will be soft, and come together into a large ball shape.
• Use your hands or a tablespoon to roll the mixture into small balls (about 2 teaspoons / 1 tablespoon per ball).
• Place the cookie balls in the baking tray, making sure that there is 1 ½ inch space between each cookie. Use a wooden spoon, or the back of a chopstick, or your little finger to create an indent in the middle of the cookie.
• Use a teaspoon to carefully place a small amount of jam into each indent. Place the trays into the fridge and chill for 15 – 30 minutes. This step is to prevent the cookies from spreading too much.
• Bake the cookies for around 8 – 12 minutes until pale golden from top, and the jam has set.
• Let the cookies cool on the baking tray for a couple of minutes, and then transfer to a wire rack to cool completely. Dust with powdered sugar before serving.

Notes:

• Use a small amount of jam to fill each indent. Otherwise the jam will run during the baking. Fill the jam till it almost comes to the top of the indent.
• If the biscuit dough is sticky and difficult to handle, add another tablespoon of flour to help it come together. Or keep the dough in the fridge for 10 - 15 minutes. The cold temperature helps the butter to solidify making the dough easier to handle.
• Chill the biscuits before baking. This step is necessary to prevent the biscuits from spreading.