Preheat deep fryer or oil to 350˚F.
Filling: Place all ingredients into a mixing bowl and stir together until fully combined. Season with salt and pepper and set aside.
Pour stock, oil and salt into a medium pot and simmer. Once the mixture has come to a simmer, add flour and whisk together with a wooden spoon. As dough forms it’ll be harder to stir, but make sure to continue to vigorously stir for about 2 minutes or until a barely sticky dough forms and no dry spots remain.
Remove from pot and allow dough to cool on a clean surface. Once dough is cool enough to handle, take about 3 tablespoons at a time and create a ¼ inch disc in your palm. (if dough get too sticky, wet your hands a little with cold water)
Place 2 teaspoons of filling into the center of the disc and bring the edges of the disc up into the center and pinch up and seal to create a tear drop.
Gently roll the tear drop into the lightly beaten egg whites followed by a thin layer of bread crumbs. Set aside. Continue until all the coxinha have been made.
Fry each coxinha on each side for 3 to 4 minutes or until golden brown. Season with salt and pepper and serve immediately.