Preheat oven to 180°C. Place baking paper onto oven tray and set aside.

Place blueberries, 1 cup sugar and 1 tablespoon water into a small saucepan over a high heat. Bring to boil then reduce heat to low and simmer for 5 minutes. Add corn flour and stir consistently for 1-2minutes until mixture thickens. Remove from heat immediately and set aside to cool.

Add butter, caster sugar and ground cardamom into a mixer bowl and whisk on high for 5 minutes. Reduce heat to low/medium and gradually add in the flour.

Scoop out 2 tablespoons of mixture into your hand and shape into a ball. Roll into remaining 1/4 cup sugar and place onto baking tray. Repeat with remaining mixture.

Using the back of a teaspoon or your thumb, lightly press a hole into the centre of each cookie. Spoon 1 teaspoon of blueberry mixture into each cookie and place into the oven for 10-12 minutes.

Remove from oven and place on cooling rack to cool completely before serving. Store in an airtight container.