Preheat oven to 180°C. Grease deep 20cm round decorative fluted cake pan.
Split vanilla bean lengthways and scrape seeds into large bowl. Add butter, honey, eggs and sour cream; whisk until combined.
Sift flour and caster sugar over honey mixture and stir until just combined.
Pour mixture into pan. Bake cake 30 minutes. Cover cake loosely with foil, bake a further 30 minutes. Remove foil; bake about a further 5 minutes or until a skewer inserted in centre comes out clean. Cool cake in pan.
Turn cake onto serving plate and dust with sifted icing sugar.