Ingredients (makes 18 squares)

• 150 g butter, softened at room temperature
• 3/4 cup caster sugar
• 1 teaspoon vanilla essence
• 3 eggs
• 1 1/4 cup self-raising flour
• 1/2 cup walnuts roughly chopped
• 1 cup frozen blueberries
• 1 punnet fresh blueberries
• 250 g mascarpone
• 100 g icing sugar
• 1 teaspoon lemon juice

Method

1. Preheat oven to 180C. Grease and line a 20x30cm rectangular baking tin with greaseproof paper.
2. Cream together the butter, sugar and vanilla essence until pale and fluffy. Add in the eggs, one at a time, beating well after each addition.
3. Sift the flour into the bowl and genlty fold through the using a large spoon or spatula, add in the walnuts and blueberries and gently fold through. Spoon the mixture into the prepared tin and spread evenly and then bake for 25-30minutes until golden and risen. Leave to cool in the tin, then turn out onto a rack to allow to cool completely before icing.
4. To make the icing, sift the icing sugar into a bowl, add in the mascarpone and lemon juice and whisk together until smooth. Spread over the cake, then cut into squares and top each one with a blueberry.

Notes

If you are short on time the cake can be enjoyed without icing as it is very light and moist on its own. When spooning the mixture into the pan it may appear that there is not enough, but don't panic the cake will rise so just make sure you spread it evenly over the whole tin.