Start by pouring the broth into a stockpot. Add the roasted turkey and bring to a boil.
Reduce to a simmer and add the orzo.
Meanwhile, juice two lemons to get ½ cup of lemon juice. If your lemons do not have enough juice for ½ cup, you may need to use a 3rd lemon.
Separate the whites from the egg yolks and put the yolks into a blender. The whites can be used for a different recipe like an egg-white omelet, or for making a meringue.
Blend the egg yolks with the lemon juice for about 2 minutes until the mixture is foamy and frothy.
Take 2 ladles full of the hot broth and slowly pour into the blender, while blending to temper the eggs. Don't add all at once - stream it into the whirling blender so you don't scramble the eggs. Add the 2nd ladle full - about 1 cup total to the broth. The egg-lemon sauce should be foamy and frothy and ready to be added to the soup.
Turn the heat off the stove.
Slowly pour the egg-lemon mixture into the pot, stirring slowly.
Cover the pot and let it sit for about 5 minutes.
Serve with fresh cracked pepper.