Start by preheating the oven to 180°C/350°F. Then cream the butter and sugar together until light and fluffy. Gradually add the eggs one at a time, beating in between. Then fold in the flour and vanilla extract.
Line a 9-inch tin with nonstick baking paper and then lay the pears in the bottom, with the skin side down. Spoon on the cake mix and spread evenly.
Bake for 30 minutes or until the cake has risen and a skewer comes out clean.
While this is cooking make the caramel. Pour the sugar into a saucepan and add the water, mix so all the sugar is moistened, but not up the sides of the pan. Place onto the heat and bring to the boil. Do not stir it, but shake the pan slightly to spread when it starts to go brown and caramelise.
When it is a deep caramel colour, take off the heat and carefully add the cream. It will splutter and spit, so be careful. Then add the brandy and small splash of water. Place back onto the heat and cook until all combined. You can stir at this point.
When the cake is cool, turn out onto a plate so the pears are on top then pour over the sauce. Serve with cream or custard.