Place the butter in a bowl, whisk in the sugar and salt. Add the eggs one at a time and continue to whisk until the mixture becomes lighter in colour. Stir in the buttermilk.
Mix together the flour, poppy seeds, baking powder and sodium bicarbonate, whisk into the butter mixture. Transfer the mixture to the prepared tin.
Mix the flakes, flour and sugar in a bowl. Add the butter and rub by hand to form a crumbly mixture. Arrange the cherries on top of the cake, sprinkle with the crumble topping.
Approx. 1 hr. in the lower half of an oven preheated to 180°C. Remove, allow to cool slightly, remove the tin frame, slide the cake onto a cooling rack, leave to cool, dust with icing sugar.