In a large bowl, combine ground meat, crushed saltine crackers (or panko), buttermilk (or egg), parsley, thyme, garlic powder, onion powder, salt, and pepper until just combined. Shape into 14 – 16 1-1/2-in meatballs.
Heat the Instant Pot in sauté mode. Add oil and brown the meatballs, about 2 minutes per side. Add sliced mushroom and garlic and cook for 2-3 minutes before stirring; cook until fragrant, about 2 more minutes.
Add beef stock, heavy cream and bay leave, cover and lock the lid. Cook high pressure 10 minutes.
Meanwhile, mix in a small bowl the cold water and cornstarch until no lumps.
When the cooking time is over, turn off the pot and carefully release pressure. Open the pot. Select “sauté” mode and adjust to less. Add cornstarch slurry, sour cream and mustard; mix to combine. Cook for 2-3 minutes until the sauce thickens.
Sprinkle with fresh parsley, if desired. Serve immediately with mashed potatoes, rice or noodles.
You can substitute the crushed saltine crackers for 1/2 cup of panko. To make this recipe KETO friendly, substitute panko for almond meal.I use buttermilk because of my daughter is allergic to eggs, but If you don't have any food restriction you can substitute the buttermilk for 1 egg.You could also use frozen meatballs or steak strips with this recipe. If using steak strips increase the cooking time to 15 – 20 minutes.To make this Meatball Stroganoff with the slow cooker mode adjust cooking time to low for 4 hours.If you don’t like mushrooms you could substitute sliced potatoes if you would prefer, or leave them out altogether.For stovetop instructions click here.