Preheat the oven to 425 degrees.
Make the sauce by mixing all the ingredients for the sauce together in a small bowl and set aside. This sauce will benefit from sitting for a while.
Process the onion and garlic in a food processor until they are very fine-set aside and make sure to save all the liquid with them.
In a large glass bowl mix all the meats together by hand to integrate completely.
Add the onions, garlic, eggs, herbs and spices and water to the meats and continue to mix together by hand until thoroughly combined.
Mix in about ⅔ of the breadcrumbs. This will tighten the meat mixture up so you can form it into loaves. Add the remaining breadcrumbs and more water if needed so that it makes a firm loaf.
Form into a loaf or loaves. Since its 3 pounds of meat, this will make a very large loaf or two or three smaller loaves depending on your needs. Extra loaves can be frozen before cooking or after baking, and saved for another meal.
Spray a roasting pan with non stick spray and set meatloaf on it.
Place the meatloaf in the preheated oven, uncovered, for 30 minutes. After 30 minutes, remove from oven and lower the oven temp to 325 degrees.
Pour off the excess grease from the roaster, cover with aluminum foil and return to the 325 degree oven for 45 minutes.
After 45 minutes, take the meatloaf out of the oven and uncover. Increase the oven temp to 425 degrees.
Pour the sauce over the meatloaf and return to the 425 degree oven, uncovered. Roast for another 15 to 20 minutes, the sauce should be bubbly and starting to brown. Remove the meatloaf from oven and rest for about 10 minutes before slicing.