Let’s walk through this incredibly simple slow cooker process:

1. Combine Most Ingredients:

• Place the beef stew meat cubes, chopped onion, minced garlic, and sliced mushrooms directly into the insert of your slow cooker.
• Pour the beef broth and Worcestershire sauce over the meat and vegetables.
• Sprinkle in the dried thyme, salt, and pepper. Stir everything together gently to combine.

2. Cook:

• Cover the slow cooker securely with the lid.
• Cook on the LOW heat setting for 7-8 hours OR on the HIGH heat setting for 4-5 hours. The beef should be very tender and easily fall apart when prodded with a fork.

3. Thicken Sauce (Optional) and Add Sour Cream:

• About 30 minutes before the total cooking time is up, prepare to finish the sauce.
• (Optional Thickening): If you desire a thicker gravy, whisk the 2 tablespoons of cornstarch with 2-3 tablespoons of cold water in a small bowl until smooth. Stir this slurry into the liquid in the slow cooker.
• Stir the sour cream into the slow cooker until it’s well combined and the sauce is creamy. Ensure the slow cooker is on LOW or WARM, or even turned off, when adding sour cream to prevent curdling.

4. Finish Cooking/Heating Through:

• Replace the lid and allow the mixture to cook (or simply heat through if thickener wasn’t added right at the end) for the remaining 30 minutes, allowing the sour cream to warm up and the sauce to thicken (if using cornstarch).

5. Serve:

• Remove and discard the bay leaf if you added one (not listed, but common). Taste the sauce and adjust salt and pepper if necessary.
• Serve the hot Slow Cooker Beef Stroganoff generously over cooked egg noodles or fluffy rice. Garnish with chopped fresh parsley.

Classic comfort food made incredibly easy!