Preheat oven to 400 °F
Line a rimmed baking sheet pan with parchment paper.
Lightly flour your work surface and lay out the puff pastry on top. Sprinkle the pastry with a bit more flour and roll it out to about a 10 x 11 inch rectangle. I used Pepperidge Farm puff pastry. Depending on the brand you use, you may end up with a slightly larger rectangle.
Transfer the dough to the prepared sheet pan. Don't worry if the edges aren't perfect. This is a very rustic tart and I'm a huge fan of imperfection. If you prefer to trim the edges to make them more uniform, be my guest. I won't tell anyone. Refrigerate the dough while you prepare the filling. It's very important that it stays cold as that will allow the dough to puff up nicely once it's in the oven.
Peel, core and half the pears. Cut each half crosswise in 1/4 inch slices.
Shingle the pears along the outer edge of the dough. Then continue to make concentric circles working towards the center of the tart until all of the pastry is covered. I tend to use the smaller slices to fill in gaps as needed at the end.
Mix the sugar and cinnamon together in a small bowl and sprinkle over the pears. I know this seems like a lot of sugar but this is necessary to achieve caramelization. Trust me.
Dice the butter in small cubes and sprinkle evenly over the pears.
Place in the oven and bake for approximately 45 minutes until the edges are brown. Don't be alarmed when the juices run off onto the sheet pan and burn This will make a huge mess of your pan but not the tart. *Note: Once cooled place your pan in the sink, add a bit of dish liquid and some warm water. Let it to soak for about 10-15 minutes allowing the burnt juices to melt away. Remove the tart from oven. Heat the jam together with the pear liquor until melted. Brush the tart completely with the mixture (including the edges).
Using a large metal spatula, gently slide the tart onto a cutting board to keep it from sticking to the parchment paper.
Allow to cool. Slice and serve at room temperature or slightly warmed with a scoop or two of vanilla ice cream and a generous drizzle of the brandy caramel on top.