In a large dutch oven, saute the onions and garlic in a small amount of olive oil seasoned with a pinch of red pepper flakes.Add the eggplant and mushrooms when the onions take on a golden color. Season with salt and pepper. Add ¼ cup of water and continue to cook, covered, until the eggplant has softened, about 15 minutes.Allow the mixture to cool slightly then, working in batches as necessary, use a food processor to finely chop and blend the ingredients. You don't want large chunks, but you don't want a puree, either.As the mix is processed, transfer it to a large mixing bowl and add the parsley and enough breadcrumbs to make a mix that can be formed into balls.Taste and adjust the seasoning as desired.Form the mix into any size balls you like.Unlike conventional meatballs, these freeze better if cooked first. Cook them at 400°F for 25 minutes or until they've browned and firmed up. They tend to stick, so use a lot of oil or a silicone mat.After the meatballs have cooled, place them in the freezer for at least an hour, no need to remover them from the baking tray if it fits. Then transfer them to freezer bags or containers for long term storage.