Cut the lean meats and the veal breast into 1-inch pieces, place in a large bowl, and add the remaining ingredients, excluding the oil.
Toss well to coat.
Cover and refrigerate the mixture for at least 3 hours or overnight.
Meanwhile, place your meat-grinding attachment in the freezer.
When youre ready to grind, pass the meat mixture through the coarse die of the grinder.
Cook a small pinch of the ground-meat mixture in a pan or skillet with a drop of oil to test for seasoning.
Adjust the salt and pepper as needed.
Divide the ground-meat mixture into 8 portions and form them into patties.
The patties can be refrigerated for up to 4 days or frozen for 2 months.
When youre ready to eat, just heat a little oil (just enough to coat the pan or skillet) and cook the patties, flipping once, until theyre browned and cooked through.