In a non-stick skillet, heat the olive oil over medium heat. Add the finely chopped onions and minced garlic to the skillet. Sauté for about 3-4 minutes until the onions are soft and translucent.
Stir in the finely chopped cremini mushrooms and cook for an additional 5 minutes, or until the mushrooms have softened and their moisture has evaporated. Remove the skillet from heat and let the mixture cool for a few minutes.
In a large mixing bowl, combine the ground chicken, plain breadcrumbs, grated Parmesan cheese, finely chopped parsley, the cooled mushroom mixture, salt, black pepper, dried thyme, smoked paprika, and lemon zest. Use your hands or a spatula to mix the ingredients gently until just combined.
Preheat your oven to 400°F (200°C).
Form the chicken mixture into meatballs, approximately 1.5 inches in diameter. Place the meatballs evenly spaced on a baking sheet lined with parchment paper.
Bake in the preheated oven for 20-25 minutes, or until the meatballs are cooked through and golden-brown on the outside.
While the meatballs are baking, prepare the creamy sauce. In a medium saucepan over medium heat, combine the chicken broth and heavy cream. Whisk the mixture together and bring it to a gentle simmer.
Season the sauce with salt and pepper to taste. Allow it to simmer for about 5 minutes, letting it reduce and thicken slightly.
Once the meatballs are done baking, carefully transfer them to the saucepan with the creamy sauce. Let the meatballs simmer in the sauce for an additional 3-4 minutes.
Serve the chicken meatballs warm, generously drizzled with the creamy sauce.
Notes
For an elegant touch, garnish with additional chopped parsley or Parmesan before serving.