This cake is so easy to make it's ridiculous, and even better theres only 6 ingredients in the cake itself!
The brown butter icing is a thing of beauty and well worth trying, but the cake does not hang on it's company - it can be served with or without it with equal success. Similarly with the candied oranges, though they have the added benefit of lasting weeks in the fridge once made!
boil 2 oranges slowly, approx 2 hours, reserve water, cool, remove seeds and whizz until smooth in a food processor - skin and all. mix together 200g caster sugar and 100g brown sugar with 6 eggs until thick, white and fluffy. add the orange paste. fold in 250g ground almonds and 1 1/2 tsps baking powder. bake in a greased and lined 26cm springform tin at 180 C for 1 - 1 1/2 hrs, covering with foil half way through if the cake is catching. make an orange syrup with 200g caster sugar and 750ml of the reserved orange water. cook 10 minutes or until syrupy. add juice and zest of 1 orange. set aside to cool, then when the cake is done, prick with a skewer and pour over the syrup.
brown butter icing. brown 200g butter slowly in pan. cool. then soften and whisk. add 400g icing sugar slowly. add 1/2 tsp vanilla extract and loosen with hot water if necessary; 1 tsp at a time.
candied oranges. wash 2 large oranges well and slice into thin slices. place in saucepan and cover with water, being careful to keep the orange slices in tact so don't pour water directly over the delicate flesh. bring to a boil and drain. bring 200g sugar, 200ml water and 2 tbsp orange juice to the boil. add orange slices in a single layer and turn down the heat. simmer for 40 - 45 minutes until peel turns translucent. place on a wire cooling rack and cool. 1 hr or overnight.