Preparation

• Grease a 10-inch tart pan with nonstick cooking spray.
• On a lightly floured work surface, roll the dough into a 12-inch circle. Gently transfer to the tart pan, pressing it against the surface and trimming off any excess dough. Prick the surface several times with a fork and refrigerate 1 hour.
• Preheat the oven to 350 degrees. Bake the tart crust 20 minutes, until golden-brown. Let cool.
• In a medium saucepan over high heat, combine the sugar, lemon juice and water and bring to a boil. Reduce the heat to medium-high and cook swirling the pan occasionally (do not stir), until the caramel reaches a dark amber color, 10 to 15 minutes. Use a clean pastry brush dipped in water to wipe away any crystals that form on the side of the pan.
• Remove from the heat and carefully whisk in the butter, then ½ cup cream. The mixture will rise and bubble. Continue to stir until smooth. Let cool 30 minutes to thicken.
• Pour the caramel into the tart shell and refrigerate until set, about 1 hour.
• In a small saucepan, bring the remaining cream to a boil over high heat, then immediately remove from the heat and add the chocolate. Let sit 2 minutes, then whisk until smooth.
• Pour the ganache over the caramel, tilting the pan so the chocolate spreads evenly. Refrigerate until set, about 1 hour.
• Sprinkle with the sea salt just before serving.