Preheat oven to 180C/350F.
Peel and core your pears and cut into eighths. Soak the pear slices in salted water to prevent browning and set aside.
Make your caramel: in an oven-safe pan over low-med heat, pour in your sugar and melt the sugar until it turns amber. If you prefer a less-sweet, more-bitter caramel then take the sugar to a slightly darker amber. If you prefer a sweeter caramel, you can just wait until every sugar granule is melted and amber and take it off the heat.
Once the sugar has reached your desired colour, take it off the heat, add in the butter and stir until well combined. Be extra careful in this step because the butter will sizzle and the sugar is hot. Your caramel is essentially done, feel free to add a touch of cinnamon for extra flavour if desired and a small pinch of salt.
Remove the pears from the salted water and pat dry with a paper towel. Arrange pears neatly on top of the caramel.
Place the sheet of puff pastry over the top of the pears and use a knife to tuck the edges of the pastry in. Bake at 180C/350F for 45-50 mins or until the pastry is golden brown. Set aside to cool.
Once cooled, flip the tart upside down onto a plate/chopping board and serve with ice cream.