Submitted by Amanda Senese (Adapted from Melissa Joulwan of Well Fed)
Preheat oven to 425 degrees. Line 2 rimmed baking sheets with parchment paper or aluminum foil (or a layer of both for easy cleanup!).
In a large bowl, combine pork, beef, parsley, salt, black pepper, and red pepper flakes.
Fold in the shredded carrot and zucchini. In a small bowl, mix together the warm water, cream of tartar, and baking soda. Add the water mixture to the meat mixture and mix to combine. Shape the meat mixture into 1-inch balls. Place onto the prepared baking sheets and bake for 20 minutes, rotating the pans front to back and top to bottom halfway through the baking time, until the meatballs are browned.
Let rest for 5 minutes and serve (or they can be frozen for up to 3 months… thaw before using).