Brown quail well in butter, then remove them from the pan and set aside.
Brown the salt pork in the same pan, stirring constantly.
Once the fat is rendered and the salt pork is slightly browned, add the mushrooms to the pan and cook until they have softened, about 2-3 minutes.
Sprinkle the all-purpose flour over the mushrooms and stir to combine.
Add the wine to deglaze the pan, stir, and cook until reduced by half, about 2-4 minutes.
Add the broth to the pan and stir to combine.
Add the quail halves and pearl onion halves to the pan, cover, and simmer for 30 minutes or until the sauce has reduced by one-third.
Garnish with the chopped parsley and serve over rice.