Adjust oven rack to the middle position and heat oven to 425 F.
Place vegetables on a large sheet pan and toss with the spices, salt, pepper and oil. Then spread the vegetables out in a single layer.
To make the meatballs, add the garlic, onion and parsley to a small food processor and pulse for a few seconds until finely chopped. (If you don't have a food processor, you can do this by hand.)
Add to a medium bowl with the ground beef, spices, salt, pepper and bread crumbs, and mix well to combine.
Use your hands to shape the meat into 1-inch balls.
Arrange the meatballs on top of the vegetables, spray them with oil and roast for 12 to 14 minutes.
Turn the oven to broil and cook until the tops of the meatballs are browned, about 1 minute.
Remove from the oven.
While the meatballs are roasting, add all of the sauce ingredients to a small bowl and whisk until creamy. If the sauce is too thick, add 3 to 4 tablespoons of water, plus more as needed, until it reaches your desired consistency.
Serve the meatballs and vegetables over rice or wrapped in a pita, and drizzled with the sauce.
