Lemon Meringue Tart                                 

For the sweet pastry dough:
1½ sticks (12 tablespoons) unsalted butter, at room temperature
2/3 cup confectioner’s sugar
¾ teaspoon vanilla extract

½ teaspoon fine salt
1 egg yolk
1¾ cups all-purpose flour

For the lemon curd:
Grated rind of 2 lemons
1/3 cup granulated sugar
1 egg
1/3 cup fresh lemon juice (from about 2 lemons)
2 egg yolks
Pinch of fine salt

3 tablespoons unsalted butter, cut into pieces and chilled 
½ cup heavy cream, chilled

For the Swiss meringue:
2 egg whites (with absolutely no yolk in it)
½ cup granulated sugar

 1. Make the dough: In a food processor, pulse the butter until creamy. Add the confectioner’s sugar, vanilla, and salt, and pulse until combined. Add the egg yolk and pulse again to combine, stopping to scrape down the sides as needed. Add the flour and pulse until just combined but still crumbly (the less you pulse, the better.) Gather the crumbs into a ball and press the ball into a puck. Cover with plastic wrap and chill for 1 hour. (Alternatively, you can make the dough using a stand mixer: mix all ingredients except for the flour on high speed, add the flour on low speed until just combined.)
2. Place the dough between two sheets of plastic wrap and using a rolling pin, roll it out to 3/16-inch thick sheet. Remove one piece of the plastic from the dough sheet and lay it dough-side down into a 9-inch tart pan. Trim the edges of excess dough. Chill for at least 1 hour.
3. Preheat the oven to 400 degrees. Set a rack in the middle of the oven.
4. Remove the top layer of plastic wrap from the dough. Cook the tart until golden brown all over, about 25 minutes. (Check the dough half way through the cooking. If it puffs up, prick it with a fork to deflate.) Cool completely.
5. Make the lemon curd: In a large bowl, work the grated lemon rind into the sugar with your fingers.
6. Bring a large saucepan with 1-inch of water to a low simmer (this will be the bottom of a double boiler.) Set the bowl of zest and sugar over the simmering water, add the whole egg and whisk until the sugar dissolves. Whisk in the lemon juice, egg yolks, and salt, and whip constantly over the simmering water until it thickens enough to hold the line of a whisk. Whisk in the cold butter, a piece at a time. Cool to room temperature. Set the “double boiler” saucepan aside.
7. Preheat the oven to 325 degrees.

8. In a medium bowl, whip the cream to stiff peaks. Gently whisk the cream into the room temperature lemon curd. Pour the mixture into the cooled tart shell. If the edges of the tart shell are dark brown, cover them with a ring of foil. Bake until the lemon mixture no longer jiggles when the pan is tapped, 20 to 25 minutes. Let cool on a wire rack at room temperature.
9. Make the Swiss meringue: Bring the large saucepan filled with 1-inch of water to a simmer. Whisk the egg whites and sugar together in the very clean bowl of a standing mixer and set over the simmering water. Whisk constantly until frothy and the sugar dissolves. Transfer the bowl to the mixer fitted with a whisk attachment and whip on high speed until the bottom of the bowl is cool and the meringue has reached stiff peaks, about 6 minutes.  
10. Preheat the oven to broil.

11. Spread the meringue over the cooled (not cold) tart, from edge to edge (this will prevent the meringue from weeping or shrinking.) Set the tart about 4 inches under the broiler, watching and rotating as needed, until browned, 30 seconds to 2 minutes. Let cool and serve immediately. It’s best the day it’s made but will keep covered in the refrigerator for up to two days. Makes one 9-inch tart, serves 8 to 12. Jill Santopietro for The Boston Globe.