Place the bread in a small bowl and pour the two tablespoons of milk over it to soften. In a separate large bowl, combine the ground beef and ground chicken. Add the grated onion, egg, soaked bread, nutmeg, cinnamon, salt, and pepper. Mix everything by hand or with a spatula until fully incorporated, but don’t overmix to avoid tough meatballs.

Form ping-pong-sized balls and place them on a baking tray lightly greased with spray. Bake in a preheated oven at 200 °C (390 °F) for 20–22 minutes, or cook them in the air fryer for 15 minutes at 190 °C (375 °F), flipping halfway through. You can also brown them slightly in a skillet with just a teaspoon of oil.

While the meatballs cook, prepare the sauce. Heat the milk in a small saucepan, and once it begins to simmer, stir in the cornstarch-water mix and the mustard. Cook over medium heat, stirring constantly, until the sauce thickens slightly. Remove from heat, wait a few seconds, then stir in the Greek yogurt. Mix well and adjust salt and pepper to taste.

Serve the meatballs hot with the sauce on top and, if you like, a teaspoon of cranberry jam. Add a bit of cauliflower mash, green peas, and roasted vegetables for a complete, satisfying meal that stays within your WW plan.