In a stand mixer fitted with a paddle attachment, mix together the flour, powdered sugar, and almond meal until combined. On medium speed, add the cold butter and mix until it starts to form a ball of dough. If it looks dry, add some ice water to bring it together. Wrap with plastic wrap and place it into the refrigerator for 30 - 40 minutes or until firm. Preheat the oven to 350F.

Place the dough onto a lightly floured surface. Roll out the dough to 1/4" thick. If you want to create mini tarts, punch out the dough large enough to fit your mold. Transfer the dough to your mold and gently press in the dough at the edges. Trim off the excess. Prick a few holes with a fork on the base to prevent the dough from puffing up. Bake for 15-20 minutes until golden brown. Let cool.

In a saucepan, combine together the sugar, cornstarch, salt, and water. Mix until combined. Place over medium heat and bring to a boil for one minute. Remove from the heat and slowly temper the yolks with the sugar mixture. Return it back to the medium heat Whisk and bring to a boil for about one minute until it;s thick. Add the lemon juice and butter. Stir to combine. Cover with plastic wrap and let it cool.

In a stand mixer fitted with a whisk attachment, add your egg whites and whisk on medium speed until foamy. Add the cream of tartar, vanilla extract, and sugar on medium speed until you get stiff peaks.

Pour the filling into the shell and spread the meringue on top. With a spoon, create some peaks to the top with the meringue. Bake the meringue for about 10 minutes or until lightly brown.