Like a creme brulee, this dessert has crunchy caramelized sugar on top. But a silky lemon filling is below, chilled in a crisp tart shell made with pate sucree.
Preheat oven to 375 degrees. Turn out dough onto a lightly floured work surface; roll to 1/8 inch thick. Press into bottom and up sides of a 13 3/4-by-4 1/4-by-1-inch rectangular tart pan (pan should have a removable bottom); trim dough along rim. Refrigerate until cold, about 30 minutes.
Line bottom with parchment paper; add pie weights. Bake shell until edges just turn golden, about 10 minutes. Remove weights and parchment; bake until golden brown, 10 to 12 minutes. Let cool completely on a wire rack.
Put lemon juice and 1 cup sugar into a heatproof bowl. Pass yolks through a fine sieve into bowl; whisk to combine. Set bowl over a pan of simmering water; whisk until thick, about 10 minutes. Remove bowl from heat; stir in zest. Stir in butter, 1 piece at a time, until it melts. Pour filling into tart shell. Refrigerate, uncovered, until firm, about 2 hours.
Place tart on a baking sheet. Remove sides from pan and place them upside down over sides of tart to prevent edges from burning. Sift 2 to 3 tablespoons sugar evenly over top of filling. Using a small butane kitchen torch, carefully caramelize sugar until it is deep amber. Tart can be stored in an airtight container at room temperature up to 1 day.