Preheat your oven to 200c and then put your small pan on the hob on a low heat. Add the butter and sugar to the pan (to make the caramel). There's not much to do here, other than stir it occasionally to help it mix together. Keep an eye on this and just keep gently mixing every 20 seconds or so, to help the mixing process.
After about 2 minutes, the butter and sugar should be pretty much melted together. Now you just need to leave it to bubble until it goes golden brown. You don't need to stir it or anything, just watch it changing colour. After about 2 minutes of bubbling away, it should start to change to golden brown around the edges. Leave it to bubble for about 30 seconds more then go and get the pears.
Carefully put the pears into the pan flat side down and cook for 3 minutes. You might only be able to fit 5 halves in depending in the size of your pears, but that's fine. Be careful with your hands as the sugar will be very hot. Don't worry about the presentation as you'll turn the pears over later and make them look pretty.
Next you need to roll out the puff pastry. Lightly dust your work surface with flour and pop the pastry on top. Lightly flour the rolling pin and begin rolling. After rolling in one direction, pick up the pastry to check it hasn't stuck, and then turn it and roll it again. You want to create a large circle, roughly the thickness of a pound coin.
After 3 minutes is up, turn over the pears, very carefully so as not to burn yourself and cook for another minute whilst you finish off the pastry. Hopefully the pears are starting to caramelise nicely! Back to the pastry and once you have a rough large circle, use your plate to cut out the shape slightly larger than your pan.
Next bring over your pan and arrange the pears in the pan so that they're all pointing into the middle, before draping the pastry disk on top. The only thing left to do is to tuck the pastry down the side of the pan, hugging the pears, as in the photo to the right. Put a few little cuts in the pastry and you're ready to bake.
Pop the pan into the oven for 25 minutes until it's golden brown. When you take it out of the oven, leave it for 5 minutes to rest slightly.
Loosen the pastry with a knife, around the side of the pan, so that when you turn it out, the pastry doesn't stick to the side. Take your dinner plate and place it on top of the pan, and whilst holding the plate onto the pan, flip the plate and pan upside down so that the plate is on the bottom, and hopefully, the tart is resting nicely on top. Drizzle any excess juices from the pan over and around the pears and you are done.
I hope that you enjoy it.