Shortbread

Melt the butter, confectioners' sugar, salt, vanilla extract, and lime zest in a bowl until well combined

Beat in the egg until smooth

Incorporate the flour, baking powder, almonds, and egg white to form a dough

If too sticky, add a little more flour

Roll out the dough on a lightly floured surface to a 30 cm x 5 cm rectangle, gently pressing down the edges

Chill in the refrigerator for 15 minutes

Remove from the refrigerator, brush with the egg white diluted in water, and bake in a medium oven until golden brown

Reduce the temperature to low and let cool for 10 minutes

Cool completely before cutting into diagonal slices 1 cm thick using a sharp knife or bread knife

Lay out the slices on a baking sheet and return to the oven for an additional 10 minutes, or until lightly toasted.