In a large bowl, combine flour, sugar and salt; cut in butter until crumbly. Gradually add water and vanilla, tossing with a fork until dough forms a ball. Cover and refrigerate until easy to handle, about 30 minutes.
Preheat oven to 400°. On a lightly floured surface, roll dough into a 10-in. circle. Transfer to a parchment-lined baking sheet. Combine the filling ingredients; spoon over crust to within 2 in. of edges. Fold up edges of crust over filling, leaving center uncovered. Combine sugar and cinnamon; sprinkle over filling. Whisk egg and water; brush over crust.
Bake until crust is golden and filling is bubbly, 25-30 minutes. Using parchment, slide tart onto a wire rack. Drizzle with caramel topping. Serve warm.
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