First, preheat your oven to 400F. Then, add egg, coconut flour, harissa, garlic, red onion and spices to a large bowl. Use a fork or whisk to stir until combined. Add in ground chicken and use your hands to gently incorporate, without over-mixing. Set aside.
Next, add sweet potato, cauliflower, chickpeas and red onion to an extra-large baking sheet (21x15"). If you don't own one this big, I recommend splitting it between two normal-sized baking sheets. Then, drizzle oil and seasonings over top. Toss to coat and spread out evenly on the baking sheet(s). There should be minimal overlap.
Scoop out 2 tbsp of the ground chicken mixture and roll into a ball. Then, nestle the meatballs onto the baking sheet. It should make about 16-18 meatballs. Transfer to the oven and cook for 20 minutes. Optionally, switch your oven to broil for about 2 more minutes to get a nice golden finish on the meatballs and veggies.
Meanwhile, add all harissa yogurt sauce ingredients to a small bowl and stir until combined and smooth. The sauce will be pretty thin.
One the sheet pan is done cooking and has cooled for a few minutes, drizzle the harissa yogurt sauce on top. Optionally, garnish with some chopped dates and fresh dill. Enjoy!
