I preheated the oven to 350 degrees Fahrenheit, then placed my ground chicken and sausage in a bowl with the breadcrumbs, garlic, parsley, milk, and egg, plus the pecorino and Parmesan cheeses.
I should confess that I didn't use fresh breadcrumbs for this recipe. As Garten says, "Store-bought is fine!" But next time around, I'll try it with fresh breadcrumbs instead to see if it helps make the meatballs taste a bit lighter.