Roll out the pastry on a floured surface to about 1/8-inch thickness. Use it to line an 8-inch-diameter tart pan with a removable bottom. Leave a little excess pastry hanging over the sides of the pan. Let rest in the refrigerator for at least 30 minutes.

Preheat the oven to 375°F. Line the tart shell with foil and fill with pie weights. Bake until set and lightly golden, 15-20 minutes. Remove the foil and weights and return to the oven to bake until golden brown, about 5 minutes longer. Remove from the oven and let cool slightly. Reduce the oven temperature to 275°F.

Whisk together all the ingredients for the filling, taking care not to aerate the mixture too much.

Trim the edges of the pastry shell level with the rim of the pan. Place the pan in the oven, then pull the oven shelf halfway out (the pan should still be level). Pour the filling into the pastry shell, then carefully slide the oven shelf back into the oven. Bake until the filling looks slightly set, about 30 minutes. Turn off the oven and leave the tart inside to cool slowly. It will continue to set as it cools. Take the tart out of the oven only when it has completely cooled, after a few hours or overnight.

For best results, make the meringue 10-15 minutes before you are ready to serve. Preheat the broiler. Toss the sugar in a pan over low heat—you do not want to melt the sugar, just heat it until it is warm to the touch. (The warmth of the sugar helps to stabilize the beaten egg whites.) Beat the egg whites to stiff peaks in a greasefree bowl. Gradually beat in the warm sugar, then continue beating until the meringue has tripled in volume and is firm and glossy.

Spread the meringue over the filling and broil, 4-5 inches from the heat source, until browned around the edges. 2-3 minutes. Alternatively, run a blowtorch over the meringue until it is nicely caramelized. Let cool briefly, then serve.