CORN STARCH??? Fuck no. What kind of dipshit would put cornstarch in avgolemeno.
Ok here. This isn't exactly a recipe, it's a post that I copied ages ago from the Epicurious forums. But it's the best advice, and makes perfect avgolemeno.
I'm 34 and have been making this since I could stand up on the stool in my Yia Yia's kitchen (my grandmother who is now 80 yrs. old). Soupa Avgolemono: 8 c. homemade chix stock, 1 c. orzo, 4 eggs/ separated, juice of 3 lemons, fresh ground black pepper. This recipe will make a perfectly balanced salty, rich, filling, comforting soup. Boil broth, add orzo and simmer until tender 20 min. Whip whites until medium peaks, add yolks beating continuously, add juice, beating. Temper eggs with 2 c. broth, adding in constant slow stream while continuing to beat furiously so you do not curdle the eggs. Add egg mixture back to remaining broth and serve. When reheating, do not re-boil - heat slowly until very warm or you may curdle the eggs. Garnish with thinly sliced lemon. I sometimes add more than juice of 3 lemons, as the sourness is the best part of the taste! You should taste lemon, richness of eggs, salt of chicken, and starch of rice, in that order and you've made it perfectly. You can also add thin pieces of shredded chicken meat (pull off bone in strips), although classic recipes don't include chicken, vegetables, garlic or any of the ingredients many reviewers added to "fix" this recipe. Try mine and you'll be hooked for life!
This sounds so fucking good. Can't wait to try it.