In a medium skillet saute half a minced yellow onion with 1 tbsp olive oil for 8 minutes. Add the garlic and chili flake and saute an additional minute. Transfer onion mixture to a large bowl.
Add the ground chicken, eggs, basil, parsley, panko bread crumbs, milk, salt, and pepper to the onion mixture. Using hands, gently mix. Form into 2 inch meatballs and place on a foil lined baking sheet. Broil meatballs for 4 minutes.
In a large pot, saute half a chopped yellow onion with 2 tbsp olive oil. Add the chicken broth, meatballs, chopped swiss card, and chopped escarole. Simmer for 10 minutes.
In a small bowl whisk together 2 egg and 3 tbsp of parmesan cheese. Slowly pour into the soup stirring clockwise. Remove from the heat.
Portion soup into large bowls and garnish with more parmesan cheese.
-If you cannot find escarole, substitute for other leafy greens like endive, spinach or kale.