Preheat the oven to 180 degrees C. Grease a 23cm flan dish with butter and dust with flour.
In a small saucepan bring the milk and vanilla bean to the boil. Remove from heat and set aside for 5 minutes for the flavour to infuse. Discard the vanilla bean and add the cream and liqueur to the milk.
In a bowl, whisk the eggs and sugar until pale. Fold in the flour, pour in the milk mixture and stir until combined. Strain into a jug.
Arrange the cherries, cut side down, in the flan dish. Gently pour in the batter. Bake for 30 minutes or until just set. Serve warm, dusted with icing sugar.