Combine all of the meatball ingredients in a medium bowl and stir will. Form into 18 meatballs. Sear the meatballs in a hot nonstick pan for a minute or two per side until firm enough to skewer.
For the sauce:
Whisk all of the sauce ingredients together in a small bowl until combined.
For the skewers:
Cut the zucchini into 1 inch chunks. Cut the onions into1 inch pieces (it’s ok if the pieces fall apart). Cut the mushrooms in half.
Thread the meatballs and vegetables onto six long skewers – 3 meatballs, 2 mushroom halves, a few onion sections, and 2 chunks of zucchini per skewer. When all the skewers are assembled, brush liberally with the sauce on all sides. Grill on high heat for about 2 minutes per side, or until the veggies are cooked to your liking and the meatballs are cooked through.
Approx nutrition info per skewer: 235 calories, 17g fat, 3g net carbs ,17g protein