Directions

1. Heat the oven to 375 degrees F. Stir the cinnamon and 2 tablespoons sugar in a small bowl.
2. Place the pear halves into a large bowl. Add the lemon juice and toss to coat. Add the cinnamon-sugar and toss to coat.
3. Unfold the pastry sheet on a lightly floured surface. Invert a 10-inch heavy, oven-safe skillet over the pastry sheet. Using the skillet as a template, trim the excess pastry to make a rough circle. Prick the pastry circle thoroughly with a fork. Place the pastry circle onto a plate and refrigerate.
4. Heat the 10-inch heavy, oven-safe skillet over medium-high heat. Pour the water in the center of the skillet. Pour the remaining sugar over the water. Cook for 7 minutes or until the sugar is a deep amber color. Do not stir. Remove the skillet from the heat. Add the salt and butter. Carefully tilt the skillet so that the sugar mixture and butter swirl together until well blended. Let the mixture cool for 2 minutes.
5. Sprinkle the walnuts in the skillet. Drain the pear halves. Arrange 11 pear halves around the inside edge of the skillet, cut-side up, overlapping slightly, with the tops pointing toward the center. Place the remaining pear half, cut-side up, in the gap in the center of the skillet, trimming to fit, if needed.
6. Cook the pears over medium heat for 10 minutes or until tender. Do not stir. Remove the skillet from the heat.
7. Place the pastry circle over the pear halves, pressing down slightly and tucking the edge in around the inside of the skillet.
8. Bake for 40 minutes or until the pastry is golden brown. Let the tarte tatin cool in the skillet on a wire rack for 5 minutes. Carefully invert the tarte tatin onto a serving plate. Serve immediately.