To make this recipe dairy free, swap the Parmesan for pine nut Parmesan or nutritional yeast. I also recommend Kite Hill's brand of almond-based ricotta.
Make-Ahead: Roast the eggplant up to two days ahead and keep refrigerated in an airtight container. You can also prepare the whole meatball mixture 1 day ahead, and remove from the fridge 20 minutes before forming into balls.
Store: Store leftover meatballs (with or without sauce) in an airtight container refrigerated up to 4 days.
Reheat: If reheating the meatballs in sauce, it's best to warm them stovetop in a small saucepan. If reheating the meatballs without sauce, either warm them gently in a skillet over medium-low heat, or in the toaster oven.