I have found this recipe and it seems to be a yummy cake.
Might be worth a try......
Blueberry Walnut Cake
75 g butter, melted
175 ml orange juice
175 ml sugar
350 ml flour
2 tsp baking powder
4-500 ml blueberries
For the topping:
125 ml chopped walnuts
50 ml brown sugar
3 tsp cinnamon
1/2 tsp cardamom (ground, or preferrably just-bashed in a pestle and mortar)
2 tbsp melted butter
Butter a springform pan, about 24 cm in diameter. Flour it or use breadcrumbs to cover the sides and bottom.
Mix nuts, brown sugar, cinnamon, cardamom and melted butter for the topping and set aside.
Stir melted butter, eggs and juice for the cake, and add the sugar.
Stir until it's well combined, and add flour and baking powder.
Don't overwork the batter.
Pour into the pan, and add about half the topping in dollops.
Run a knife through it for some marbling.
Sprinkle in the blueberries, and then the rest of the topping.
Bake at 175°C ( 347 F) for about 45 minutes.