Step 1: Prepare the Chicken Meatballs

1. Mix the ingredients: In a large mixing bowl, combine the ground chicken, breadcrumbs, parmesan cheese, egg, minced garlic, onion powder, dried parsley, salt, and pepper. Mix well until evenly combined, but avoid overmixing, as it can make the meatballs tough.
2. Form the meatballs: Using your hands or a small cookie scoop, form the mixture into 1 ½-inch meatballs. You should have about 16-18 meatballs. Place them on a plate or tray.
3. Sear the meatballs: Heat 1 tablespoon of olive oil in a large skillet over medium heat. Add the meatballs in batches, making sure not to overcrowd the pan. Cook for 3-4 minutes on each side until golden brown. The meatballs don’t need to be fully cooked at this stage as they’ll finish cooking in the sauce. Remove the meatballs from the skillet and set them aside.

Step 2: Make the Creamy Mushroom Sauce

1. Sauté the aromatics: In the same skillet, add 2 tablespoons of olive oil or butter. Add the chopped onion and sauté for 3 minutes until softened. Add the minced garlic and cook for another minute until fragrant.
2. Cook the mushrooms: Add the sliced mushrooms to the skillet and cook for 5-7 minutes, stirring occasionally, until they are browned and have released their moisture.
3. Add the seasoning: Stir in the thyme, salt, and pepper. If using Dijon mustard, add it now for extra depth of flavor.
4. Deglaze the pan: Pour in the chicken broth, scraping up any browned bits from the bottom of the skillet. Let it simmer for 2-3 minutes to reduce slightly.
5. Add the cream: Reduce the heat to low and stir in the heavy cream. Simmer for another 3-4 minutes until the sauce thickens slightly.

Step 3: Combine the Meatballs with the Sauce

1. Add the meatballs: Return the seared meatballs to the skillet, nestling them into the creamy mushroom sauce.
2. Simmer gently: Cover the skillet and let the meatballs simmer in the sauce for 8-10 minutes, or until they are fully cooked (internal temperature should reach 165°F). Stir occasionally to coat the meatballs in the sauce.
3. Finish with herbs: Stir in the chopped parsley and adjust the seasoning with more salt or pepper, if needed.

Step 4: Serve

Serve the creamy mushroom chicken meatballs over pasta, mashed potatoes, rice, or crusty bread to soak up the delicious sauce. Garnish with extra parsley and grated parmesan cheese for a restaurant-quality finish.