Step 1: Preparing the Meatballs

1. Preheat your oven to 400°F. Lightly grease a small sheet pan with cooking spray or line it with parchment paper.
2. In a large mixing bowl, combine ground chicken, chopped onion, beaten egg, breadcrumbs, and garlic. Season with salt and black pepper.
3. Take about one ounce of the chicken mixture and flatten it slightly in the palm of your hand. Place one to two small crumbles of blue cheese in the center. Carefully shape the chicken mixture around the cheese, forming a ball. Ensure the cheese is fully encased to prevent leakage during baking.
4. Repeat the process with the remaining mixture, placing each meatball onto the prepared baking sheet.
5. Lightly coat the meatballs with cooking spray to help them brown evenly.

Step 2: Baking the Meatballs

1. Place the tray in the preheated oven and bake for 18 to 20 minutes, turning the meatballs once halfway through cooking.
2. The meatballs are done when they are golden brown and cooked through. You can check by inserting a meat thermometer into the center—it should read at least 165°F.

Step 3: Making the Buffalo Sauce

1. While the meatballs are baking, melt the butter in a saucepan over low heat.
2. Add the buffalo hot sauce and whisk until fully combined. Remove from heat.
3. Once the meatballs are done baking, transfer them to the saucepan and toss gently to coat them evenly in the sauce.

Step 4: Preparing the Blue Cheese Dip

1. In a bowl, mix sour cream, crumbled blue cheese, and buttermilk.
2. Season with salt and black pepper to taste.
3. Garnish with fresh chives and an extra sprinkle of black pepper.

Step 5: Serving the Dish

1. Arrange the buffalo chicken meatballs on a serving platter.
2. Serve with celery sticks, carrot sticks, and blue cheese dip on the side.
3. If desired, provide small skewers or toothpicks for easy grabbing.