Process sugar and almond. Add zest, butter, salt and mix. Add the egg, blend to smooth and add flour and baking powder – mix to combine. Wrap up and chill until firm. Pastry can last a week in the refrigerator or kept frozen for weeks. Since that less than a third of the pastry will be used, Save leftover for more pies or cookies. Take a third of the pastry, workout to soften over a floured work surface and roll out into a thin 0.12’’/3 mm thick sheet. Lay on baking tray lined with greased parchment. Prick dough with a fork and freeze for 20 min. Trim off excess dough and refrigerate.
Use a 9.5x6.5 inch (24x16cm) baking tray lined with greased parchment. Make a day ahead. Prick a lemon a couple of times and boil for about 20 min. Cool, cut in half and remove the white membrane from the center and seeds. Save flesh, rind and juice (the whole lemon is used). Mix eggs with sugar and starch first. Add lemon juice, the cooked lemon and melted butter – blend well; set aside.
The use of a pizza stone is highly recommended when baking any crust. If not using pizza stone, pre-bake crust for 15 min. Preheat oven to 350ºF/180ºC. Pour lemon filling in the baking tray and bake for 35 min or until set. Cool and chill overnight.
Flip lemon tart over a greased parchment. Trim off edges and cut into 8 bars and chill. Bars can be kept frozen for weeks. Right before serving, top with sugar and torch to caramelize like a creme brûlée – zest some lime and serve!