Using your hands, roll bits of the sausage into small, bite-sized balls.
In a saute pan over medium high heat, add 2 tablespoons olive oil. Once it's hot, add the sausage balls and let sit for 2-3 minutes until golden brown. Turn them gently so they continue browning on the other side.
Once browned, remove from the heat and set aside. If they are still pink in the center, they will cook more in the broth, so don't worry. Remove the balls and place on a paper towel lined plate.
In a soup pot over medium high heat, place the remaining 2 tablespoons olive oil and then add the diced onions. Stir well to coat and allow to soften for about 5 minutes. Add the garlic, stir well and let cook about 2 minutes. Now add your stock of choice and bring to a boil.
Add the chopped escarole, reduce the heat to a simmer, cover and cook for 10 minutes. Add the meatballs and cook another 5 minutes.
Place two eggs in a bowl and beat lightly. Add the Parmesan and Pecorino and blend well using a fork.
Slowly pour the egg-cheese mixture into the the hot soup, stirring constantly. Cover and simmer just until the egg bits are set, about 1 minute or so. Taste and season with salt and pepper.
Ladle in soup bowls and garnish with red pepper flakes, a squirt of lemon and a grating of cheese. Serve immediately and eat in front of a roaring fire.
Store any leftover soup in the refrigerator.