Chop the vegetables: Dice one cup each of white onions, celery, carrots, and slice or dice one cup of mushrooms. Aim for uniform pieces to ensure even cooking.

Combine ingredients in slow cooker: Add chopped onions, celery, carrots, mushrooms, and beef chuck roast to slow cooker. Stir in drained diced tomatoes, salt, pepper, and parsley flakes.

Add liquids for richness: Pour in almond milk, pomegranate juice, beef broth, and tomato paste. Mix well until blended.

Optionally sear the beef: Sear the beef chuck roast in a skillet over medium-high heat for 3-4 minutes on each side, then transfer to the slow cooker.

Cook the ragu: Cover and cook on low for 8 hours or high for 4 hours, until beef is tender and easily shreddable.

Shred the beef: Remove the beef from the slow cooker, shred into bite-sized pieces with two forks, and return to the sauce.