1. Preheat oven to 160C fan-forced (180C conventional).

2. Place blueberries with 60g of the brown sugar and 1 tbsp water in a small saucepan and, over a medium heat, bring to a simmer for 2 minutes. Set aside.

3. Put butter in the cast-iron pan and place it in the oven for 2-3 minutes so the butter can melt and grease the pan at the same time.

4. In a small mixing bowl, whisk together the remaining 90g brown sugar, as well as the milk, vanilla and the melted butter from the pan.

5. Add in flour, baking powder and salt and whisk until smooth.

6. Pour mixture into the baking vessel. Use a slotted spoon to lift the blueberries out of the liquid and scatter them on top of the cake mixture.

7. Place the pan in the oven and bake for 20-25 minutes or until a skewer inserted in the middle comes out clean. 

8. While the cake bakes, reduce the syrup left from the blueberries by simmering over a low heat until it's thick and sticky. 

9. Serve a spoonful of the cake straight from the oven with a scoop of ice-cream and the sticky blueberry syrup drizzled over the top.

Note: the preferred vessel is a 23cm cast-iron pan, but any other oven-proof dish around that size will work.