Preheat the oven to 350 degrees Fahrenheit (175 degrees Celsuis). Line a sheet pan with parchment paper.
2
Slice the stem ends from the lemons so they can sit level. Cut off the tip end of each lemon, parallel with the bottom and roughly ⅓ of the way down. Reserve the tops.
3
Hold each lemon firmly and use a serrated knife to cut out the pulp. Use a melon baller to scoop out the flesh into a sieve placed over a bowl. Squeeze the juice from the pulp and reserve for later. Place the hollowed-out lemons on the sheet pan.
4
In a heat-proof bowl, combine the egg yolks, ¼ cup sugar, ¼ cup reserved lemon juice, and flour. Whisk until pale yellow. Place the bowl over a pot of simmering water and continue to whisk for about 8 minutes, until very thick. Remove from the heat and beat with an electric mixer for about 10 minutes, until cooled, while scraping down the sides. Transfer to a clean bowl and set aside.
5
In a medium mixing bowl, combine the egg whites with the remaining ¼ cup sugar. Beat with the electric mixer on low speed until frothy. Slowly increase the mixer speed until the meringue is shiny and hold soft peaks, about 2 to 3 minutes
6
Whisk about ⅓ of the meringue into the yolk mixture, then fold in the remaining meringue gently. Fill the lemon shells to just below the rim.
7
Bake for approximately 14 to 17 minutes, until the tops are golden and have risen about 1 inch above the shell.
8
Serve immediately, garnished with confectioners’ sugar and the reserved lemon tops.