In the bowl of a stand mixer fitted with the paddle attachment (or a large bowl with a wooden spoon), place the flour, xanthan gum and Expandex, and whisk to combine well with a separate handheld whisk.
Create a well in the center of the dry ingredients, and add the eggs and 4 tablespoons warm water, and mix to combine on medium speed for about 1 minute (or with the wooden spoon for at least 2 minutes).
The dough should come together. If there are any crumbly bits, add the remaining warm water by the teaspoon until the dough holds together well when squeezed with your hands.
Turn the mixer speed up to medium-high, and beat until smooth, 3 to 4 minutes (or by hand with a wooden spoon for at least twice as long).
The dough should be smooth and pliable. If it feels stiff, add a few more drops of water and mix in until pliable. It should be, at most, slightly sticky but mostly just smooth.
Let the dough rest.
Transfer the dough to a piece of plastic wrap, wrap it tightly and allow it to sit at room temperature for about 10 minutes. The dough will absorb more water and any remaining stickiness should dissipate.
Shape the wrappers.
Unwrap the dough, divide it in half and return half of it to the plastic wrap and wrap tightly to prevent it from drying out.
Place the remaining half of the dough on a lightly floured surface, sprinkle lightly with more flour and roll into a rectangle about 1/4-inch thick.
Flip and shift the dough often to prevent it from sticking, sprinkling very lightly with more flour as necessary to allow movement.
With a pizza wheel, pastry cutter or sharp knife, trim the edges of the rectangle to create even edges. Remove and gather the trimmings, and set them aside.
Using even and sustained, but not aggressive, pressure, roll out the rectangle until it is approximately 1/8 inch thick. Slice into 3-inch squares.
Alternatively, slice the 1/4-inch thick rectangle into 1 1/2-inch squares, and roll each square evenly in all directions until it doubles in surface area and is 1/8-inch thick. I often find this the quicker, easier way to get squares that are the proper thickness.
How to store the raw wrappers.
Stack any raw wrappers, wrap first in waxed paper and then place in a freezer-safe container, seal tightly and freeze until ready to use.
Defrost by placing overnight in the refrigerator before using.
To make wonton soup.
In a small bowl, combine the ground pork or beef, 3 tablespoons gluten free soy sauce, rice vinegar, honey, and 1 chopped scallion. Mix gently to combine.
Lay out about 30 square wonton wrappers on a nonstick flat surface, and place about 1 teaspoon of filling in the center of each skin.
Moisten all 4 edges of each wonton skin with the egg wash, and close by joining two opposite corners of the skin, pressing out any air and sealing tightly.
Brush the top with more egg wash, and bring together both tips on the long side of the resulting triangle, overlapping them slightly and brushing with more egg wash to seal.
In a large stockpot, boil the 4 cups of chicken stock, seasoned with more gluten free soy sauce and more chopped scallions to taste.
Place about 10 wontons at a time in the boiling seasoned stock, for about 4 minutes per batch (or until the meat is cooked and the noodles are tender).
Remove the wontons with a strainer, divide among bowls, and wilt baby bok choy in the stock.
Divide the soup among 4 soup bowls, and serve piping hot.