Heat 4 cups of chicken stock until almost boiling, then poach the chicken breast, about 10-12 minutes.
Reserve the stock and shred the chicken breast in a food processor.
In a large skillet, sauté the onion and garlic in the olive oil over medium low heat until translucent.
Add the tomato paste and stir.
Add the chicken, the scallions, the cream cheese, and a ladle of stock.
Stir until everything is well mixed.
Season with salt and pepper to taste.
Then turn off the burner and stir in the parsley until well distributed.
Set the filling aside to make the dough.
In a large sauce pan, heat 3 cups of the reserved stock to boiling with the butter.
Then add the flour.
Reduce the heat and stir until the dough forms into a ball and separates from the sides of the pan.
Turn onto a lightly floured surface and allow to cool just enough so it can be handled.
Knead the dough until it looks smooth and silky.
Then pinch off a golf ball-sized amount of dough and roll it into a ball.
Use your hands to flatten the dough circle into a concave shell that fits in the palm of your hand.
Place a good teaspoon of the filling into the dough shell.
Shape the coxinhas by pinching the ends of the dough over the filling to form a somewhat pointed top while using your other hand to rotate the dough bottom to form a round.
Continue until all of the dough has been used.
Preheat the canola oil in a frying pan under medium heat. There should be enough oil in the pan to cover the coxinhas while they fry.
Meanwhile, whisk the eggs and milk in a bowl.
Pour the bread crumbs into another bowl.
Then coat each coxinha in the egg wash and then dredge in bread crumbs until they are fully coated.
Repeat until all the coxinhas have been breaded.
Fry three at a time in the oil until they are a dark golden brown.
Transfer to a paper-covered tray to drain.