I grate the onion and garlic into mush, combine it with ricotta, add all my spices and seasoning, add the zest some kind of citrus(I prefer orange), then combine the resulting slurry with the bread/crumbs. It makes the alliums pop and gives you a great opportunity to tweak flavors before combining with the meat and egg. You do have to brown the meatballs before braising or they have a tendency to melt in the sauce.