Heat a large nonstick skillet or set the Instant Pot to saute and spray with oil; saute the onions over medium heat until golden, stirring 2 to 3 minutes. Remove and divide in two.
In a large bowl, combine half of the sautéed onions with the ground turkey, bread crumbs, egg, 2 tbsp of the parsley, milk, 3/4 tsp salt and black pepper. Gently shape into 20 meatballs.
In a blender combine the water, sour cream, flour, tomato paste, boullion, Worcestershire sauce and paprika, blend until smooth.
Heat the skillet or Instant Pot back on saute, add the oil and brown half of the meatballs without disturbing (in two batches) about 2 minutes until no longer sticks, turn and brown an additional 2 minutes, set aside on a dish and repeat with remaining meatballs.
Place all the meatballs and remaining onion into the Instant pot, Slow Cooker or a large saucepan and pour the sauce over the meatballs along with the thyme and mushrooms.
For the Instant Pot:Cook on high pressure 10 minutes. Let the pressure release on it’s own. When done, discard thyme, add the chopped parsley and serve over your favorite noodles. *see note above about avoiding burn notice.
For the stove top:Add 2 tbsp water, bring to a boil then cook covered on low 20 to 25 minutes. When done, discard thyme, add the chopped parsley and serve over your favorite noodles.
For slow cooker:Cook on low 6 to 8 hours. When done, discard thyme, add the chopped parsley and serve over your favorite noodles.