Cut meat into 1-inch cubes; discard any large pieces of fat.
Combine 1 tsp salt, ¼ tsp black pepper, and season the beef on all sides.
Heat oil in a large skillet and sear the meat on all sides. Transfer to the crockpot.
Add potatoes, onions, carrots, celery, chopped garlic, butter, and bay leaves into the pot.
Whisk the broth, mustard, tomato paste, worcestershire sauce, flour, ½ tsp salt, and paprika in a bowl. Pour into the crockpot.
Cook on low for 7 to 8 hours or on high for 3½ to 4 hours, until the vegetables are tender and the potatoes are fork-tender.