Preheat the oven to 180°C / fan oven 160°C / Gas Mark 4. Grease a 21cm (9 inch) round non-stick cake tin with a little sunflower oil.
Sift the flour and baking powder into a bowl. Add the butter, then rub it in with your fingertips until the mixture resembles fine breadcrumbs. Stir in the sugar.
Add the blueberries, carrot, apple and beaten eggs to the mixture, stirring gently with a large metal spoon until combined. Tip into the cake tin and level the surface.
Bake for 40 minutes, until risen and firm to the touch. Cool in the tin on a wire rack for 20 minutes, then carefully remove from the tin and cool completely.
When cool, cut the cake into wedges and serve with Chantilly cream, sprinkled with pomegranate seeds.
Place the cream into a large bowl, make a well in the centre and sift in the icing sugar. Add the grenadine and fold it through the mixture very gently until partially incorporated to give a pretty effect.
