Mix the oil, sugar and eggs in a bowl.
Whisk to obtain a creamy mixture.
Add the flour and yeast, mix again and pour the mixture into a lightly greased round, high-sided cake tin.
Peel the pears, cut into thick slices and arrange in a rose shape on top of the cake mixture.
Sprinkle on a little icing sugar and bake in a moderate oven (180°C) for approximately 1 hour.
Leave to cool and turn out onto a rack.