Heat a large ovenproof non-stick frying pan over a medium heat. Add the water and sugar, and stir until the sugar is dissolved.
Add the vanilla bean, pears, and lemon juice. Cook for 15 minutes, or until the pears are soft. Remove from the heat and set liquid topping aside while you make the cake base.
In a stand mixer fitted with a whisk attachment, whisk the eggs and sugar until pale, thick, and about 3 times its original volume.
Switch the mixer to its lowest speed and sift in the self raising flour. Fold through before adding the almond meal, oil, and lemon juice.
Pour the cake mixture on top of the poached pears and bake for 40 minutes or until a cake tester comes out cleanly.
To serve, turn out onto a cake platter and serve as is or with some freshly whipped cream.