Butter a round cake tin, approximately 20cm wide. Preheat the oven to 180°C/gas mark 4.
Sift the flour, baking powder and sugar, and add the ground almonds. Whisk the butter with the orange zest until pale, then add the eggs one at a time. Fold in the dry ingredients with a metal spoon. Pour the mixture into the cake tin and bake in the preheated oven for 45 mins or until cooked.
Meanwhile make a syrup by boiling the orange juice with the brown sugar. Leave to cool. Once the cake is cooked, prick several times with a skewer to the base and pour on the cooled syrup. Leave the cake to cool completely before brushing on a little warmed marmalade and sprinkling it with a few toasted, sliced almonds.
Lovely served with orange segments marinated in a generous splash of whisky and a little demerara sugar.
Recipe extract from Michel Roux: A Life in the Kitchen by Michel Roux Jr. published in hardback by Weidenfeld & Nicolson, £20. Available from Amazon