Makes one 9 inch cake
1 First, line the bottom of a 9-inch springform tin with baking paper, and then grease it well. Preheat your oven to 170C/150C fan/Gas Mark 3, and place a tray or piece of foil on the bottom to catch any caramel drips.
2 Prepare the upside-down bit. Make the caramel by heating 100g of your butter, 200g of caster sugar and the lemon juice together in a pan, stirring until melted. Pour onto the base of your tin and arrange the pears on top.
3 Into a large bowl, weigh 250g of butter and 250g of caster sugar. Using an electric whisk or a wooden spoon, beat them together until smooth.
4 Add the eggs, one at a time, beating well after each addition. Then add the yoghurt and scrape in the vanilla seeds and beat them in. This is likely to curdle and don’t worry if it does.
5 Gently fold in the flour and baking powder using a large metal spoon, just enough to combine. If it isn’t at a dropping consistency, stir in a touch more yoghurt.
6 Carefully pour your mix onto your fruit and bake in the oven for approximately 40-50 minutes, or until golden brown and springy and a skewer comes out clean.
7 Leave to cool for at least 15 minutes before removing the sides of the tin (running a knife around the edge if necessary), then placing a plate or cake stand on top of it. Turn the whole thing upside down before carefully peeling away the base paper. Serve hot or cold.