Trim excess fat from 3 lb chuck roast and place the roast in the slow cooker.

Pour 1 cup water around the chuck roast in the slow cooker.

Season the beef with 1 tsp roasted beef base, 2 tsp salt, 1 1/2 tsp onion powder, 1 tsp garlic powder, and 1/4 tsp ground black pepper.

Cover and slow-cook the beef on high for 4 to 5 hours, until it is fork-tender and shreds easily.

Remove the tender beef from the slow cooker and shred it with two forks.

Thinly slice 1 package button mushrooms, 1/2 yellow onion, and 2 garlic cloves.

Melt 2 tbsp butter in a large skillet over medium heat.

Sauté the sliced yellow onion and button mushrooms in the butter for about 15 minutes, until deeply browned and rich in color.

Add the sliced garlic and 1 tbsp fresh thyme leaves to the skillet.

Stir in 1 1/2 tbsp tomato paste, 1 1/2 tbsp roasted beef base, and 2 tbsp all-purpose flour.

Cook the flour mixture for 2 to 3 minutes, stirring continuously to prevent sticking.

Add 2 tsp Worcestershire sauce, 1 tbsp Dijon mustard, and 2 cups water to the skillet.

Bring the gravy to a gentle simmer and stir until smooth and slightly thickened.

Gradually stir in up to 1/2 cup heavy cream, stopping when the gravy reaches the desired pale creamy color.

Fold about half of the shredded beef into the creamy mushroom gravy and warm through for 3 to 5 minutes.

Cook 12 oz egg noodles in boiling water according to package directions, then drain them in a colander.

Serve the beef stroganoff over egg noodles and garnish with chives and sour cream.