Whisk the dry ingredients together. Separately, beat eggs until frothy and add milk. Combine wet and dry. Add more flour if the dough is too sticky. Roll out a rectangle about 1/2" thick between two sheets of parchment paper. Refrigerate 30min. Pound the shortening to 1/8" thick between two sheets of parchment paper. Remove dough from fridge, sprinkle with flour, and roll to 1/4" thick. Repeat this three step procedure five times: - Peel off one side of the parchment, flip then peel and remove the other side. - Spread shortening over the top two thirds of the dough, fold the bottom third up and the top third down to create three layers separated by shortening. - Rotate dough 90 degrees, place parchment on it, and roll out to 1/4" thick. Refrigerate 30min-1hr. Preheat oven to 450°F. Line baking sheet with parchment paper. Peel off one side of the parchment, flip then peel and remove the other side. Using a pizza cutter, cut dough into about 12 tall triangles about 3" wide at the base and 6" tall. Starting at the widest side, roll up the croissants, and slightly curve the ends. Brush with egg white and sprinkle with sugar. Bake 10min.