01 - Preheat oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large bowl, combine ground turkey, breadcrumbs, egg, parsley, garlic, onion, thyme, salt, and pepper. Mix until just combined, being careful not to overwork the mixture.
03 - Shape the mixture into 20-24 small meatballs, approximately 1 tablespoon each. Place them on the prepared baking sheet, spacing evenly.
04 - Bake for 15-18 minutes until lightly browned and cooked through, reaching an internal temperature of 165°F. Remove from oven and set aside.
05 - While meatballs bake, heat olive oil in a large skillet over medium heat. Add sliced mushrooms and chopped onion. Sauté for 5-6 minutes until softened and golden brown.
06 - Add minced garlic to the skillet and cook for 1 minute until fragrant, stirring constantly to prevent burning.
07 - Sprinkle flour evenly over the vegetables. Stir well to coat and cook for 1 minute, allowing the flour to cook slightly and lose its raw taste.
08 - Gradually whisk in chicken broth, scraping up any browned bits from the bottom of the skillet. Add Worcestershire sauce and Dijon mustard. Bring to a gentle simmer and cook for 3-4 minutes until sauce thickens enough to coat the back of a spoon.
09 - Lower heat to medium-low and stir in sour cream until completely smooth and incorporated. Season with salt and pepper to taste. Do not let the sauce boil after adding sour cream to prevent separation.
10 - Add baked turkey meatballs to the sauce. Simmer gently for 5 minutes until meatballs are heated through.
11 - Portion cooked egg noodles onto plates or shallow bowls. Top with meatballs and sauce. Garnish with freshly chopped parsley and serve immediately.