Step 1

Preheat oven to 180°C (160°C fan-forced). Grease a 23cm x 8.5cm loaf pan, line base and sides with baking paper.

Step 2

Beat the butter, sugar and lemon rind in the bowl of an electric stand mixer with a paddle attachment and beat for 5 minutes until pale and fluffy.

Step 3

Add eggs one at a time, beating well after each addition. Fold in the flour then sour cream and mix until combined. Stir in the lemon juice and fold in the blueberries. Spoon into the prepared pan; smooth the top.

Step 4

Bake for 1 hour 15 minutes, or until a skewer inserted into the loaf comes out clean. Cool in tin for 20 minutes, then turn onto a wire rack and cool completely.

Step 5

MASCARPONE ICING Combine the mascarpone, cream, icing sugar and vanilla in the bowl of an electric mixer and beat on medium speed for 1 minute or until firm peaks and spreadable.

Step 6

Line the same loaf pan with baking paper allowing a 4cm overhand. Return the cooled cake to the pan and spoon the icing onto the cake. Refrigerate for 1 hour or until the icing firms up.

Step 7

To serve, using the overhang baking paper, carefully lift the cake out of the pan. smooth the side edges and sprinkle with the lemon rind.