01 -
Melt the butter in a pot over medium heat.
02 -
Add in the onions and celery, and saute until softened.
03 -
Mix in the oregano, matchstick carrots, garlic, and chicken, and saute for another minute.
04 -
Pour in the chicken broth, cover, and bring the mixture to a low boil.
05 -
Stir in the orzo, cover, and simmer for another 10 minutes.
06 -
Whisk together the egg yolk and lemon juice in a bowl, and spoon in a few ladles of the broth from the soup, whisking continuously while you do.
07 -
Pour the egg yolk mixture into the pot, and stir to combine.
08 -
Season with salt and pepper to taste before serving.