Step 1Cream the butter and sugar together in the bowl of a standing mixer fitted with a paddle attachment until it has a creamy consistency. Alternatively, cream the butter and sugar together in a large bowl using a hand mixer. With the mixer on, add the egg yolk until it is incorporated, then add the egg and incorporate completely.
Step 2In a separate bowl, sift together the almond flour, flour and baking powder. Add the dry ingredients to the mixing bowl slowly and continue mixing until the dough is thoroughly combined. The dough should be slightly sticky but not wet. If the dough is too dry and crumbly, add up to 1 tablespoon of water to moisten the dough.
Step 3Divide the dough into two equal portions. Shape each portion into a circle and cover tightly with plastic wrap. Refrigerate one of the portions, and allow it to rest for at least 1 hour. The remaining portion can be frozen for up to 6 months. (For frozen dough, thaw in the refrigerator before using.)
Step 4Heat the oven to 350 degrees. Remove the chilled dough from the refrigerator, and place on a lightly floured work surface. Roll out the dough into a circle slightly less than one-fourth-inch thick and about 12 inches in diameter. Gently drape the dough into a 9-inch pie pan, and trim off any excess dough so that the crust is flush with the sides of the pan. With a fork, prick holes all over the dough to allow steam to escape during baking. Bake until golden brown, 15 to 25 minutes. Allow to cool on a rack.
Step 1In a large heat-proof mixing bowl (you should be able to set it over a large pan or stock pot of simmering water to form a bain-marie), whisk together the eggs, egg yolks, sugar and lemon zest. Whisk in the lemon juice.
Step 2Fill a small bowl with water, and insert the gelatin sheets to allow them to soften. Place the butter cubes into a medium bowl and set aside.
Step 3Place the bowl with the lemon curd over a larger pot of gently simmering water to form a bain-marie. Cook the curd, stirring gently but constantly, until the curd begins to thicken and will lie on top of itself. Watch carefully to make sure the heat is not so hot that the eggs scramble. Immediately remove the curd from the stove, and pour the curd into the bowl with the butter. Remove the gelatin sheets from the water, wringing out any extra moisture, and add to the curd mixture. Gently stir the curd with a spatula to melt and incorporate the butter and gelatin into the mixture.
Step 4Pour the lemon curd into the prebaked pie shell. Cover the surface of the curd with plastic wrap, and place in the refrigerator for at least a few hours, preferably overnight, until the curd is set.
Step 1Place the sugar in a medium saucepan. Add one-half cup water, and stir with the sugar until it is the consistency of wet sand. Place the saucepan over medium-high heat, and cook the sugar until a thermometer inserted reads 240 degrees. (The sugar will form a firm ball when a little is dropped into a bowl of cold water).
Step 2While the sugar is cooking, begin whipping the egg whites. Continue beating until the whites form stiff peaks, but be careful not to over-beat.
Step 3When the sugar is ready, immediately remove it from the heat, and pour it into a heat-proof measuring cup to stop the cooking process. With the mixer speed on low, carefully begin pouring in the sugar, watching that the sugar does not touch the wire beaters and splatter. Once all of the sugar is added, increase the mixer speed to medium, and continue beating until the meringue cools and is very fluffy.
Step 4Remove the chilled lemon pie from the refrigerator and remove the plastic wrap. Spoon the meringue on top of the curd with a rubber spatula, forming a dome on top of the pie. To toast the meringue (which is optional), use a small hand torch and lightly torch the meringue until it is golden brown. Serve immediately.