Beat the butter and caster sugar together in a bowl until pale and fluffy. Add the eggs, a little at a time, beating well after each addition. If the mixture starts to curdle, add 1 tablespoon of the flour. Fold in the flour, ground almonds and baking powder using a large metal spoon and tip into a greased 20 cm (8 inch) spring form cake tin and use a palette knife to even out the mixture.
Arrange the pear halves over the top of the cake and bake in a preheated oven, 190°C (375°F), Gas Mark 5, for 25 minutes. Sprinkle the flaked almonds over the top and return to the oven for a further 10 minutes. The cake is ready when a skewer inserted into the centre of the cake comes out clean.
Leave the cake to cool in the tin, then carefully remove the ring and base. Dust with icing sugar before serving with Mascarpone, Marsala & Orange Cream (see below), if liked.