Preheat the fan forced oven to 180°C. Grease and line the base of a 20cm spring form cake tin with baking paper.
For the poached apples, place all ingredients in a large high-sided frying pan and bring to the boil over a high heat with lid on. Reduce heat to low and simmer for 10 minutes or until tender.
Remove apples from heat and strain reserving the liquid. Place the frying pan back over a high heat and add the extra 1 tbsp of extra virgin olive oil, add the cooked apples and sauté until they start to colour, remove from heat.
Arrange caramelised apple pieces in the base of prepared cake tin.
For olive oil cake, beat egg whites in a small bowl until soft peaks form. Gradually add half the sugar and beat until sugar has dissolved.
In a separate bowl, beat yolks remaining sugar until pale.
Sift in the flour and baking powder, pour in oil and 60ml reserved apple poaching liquid and mix to combine.
Gently fold in meringue, a third at a time until combined.
Pour mixture into prepared cake tin and bake for 35–40 minutes or until pudding cake springs back to the touch. Remove from the oven and allow to cool in tin for 5 minutes. Once the pudding cake has cooled slightly remove the spring form tin and flip / invert the pudding over on to a wire cooling rack.
For glaze, add caster sugar to remaining reserved poaching liquid (but put aside 30mls for the sabayon) in a small saucepan. Place over a medium heat and stir until sugar has dissolved. Bring to the boil and cook for 2 minutes or until the liquid has reduced by half.
For sabayon, place all ingredients in a heat proof bowl and place over a water bath. Whisk until pale, light and frothy, not allowing the bowl to touch the water.
Control applied heat by removing bowl from the heat occasionally to cool mixture and to avoid over-cooking the yolks. Whisk mixture continuously and return to heat to continue cooking as required. To check consistency mixture should make a trail of the number eight.
When sabayon is a constancy of your liking remove from the heat and whisk until cool.
To serve, cut cake into thick wedges, brush with verjuice glaze and serve with sabayon.