1. Remove beef from refrigerator 20-30 minutes before cooking. Pat dry with paper towels and cut into uniform 1.5-inch cubes. Season generously with salt, pepper, smoked paprika, and thyme.

2. Halve baby potatoes to roughly match the size of beef cubes. Dice onion and mince garlic cloves by hand for best flavor.

3. In a bowl, whisk together Worcestershire sauce, soy sauce, Dijon mustard, and beef broth. Set aside.

4. Add 2 tablespoons butter to the bottom of a 6-quart slow cooker. Layer halved potatoes on the bottom.

5. Scatter diced onions and minced garlic over the potatoes. Arrange seasoned beef cubes on top in a single layer if possible.

6. Pour the prepared sauce mixture over the beef. Dot the remaining 4 tablespoons of butter across the top of the beef.

7. Cover and cook on LOW for 7-8 hours or HIGH for 4-5 hours, until beef is fork-tender and potatoes pierce easily with a knife.

8. In the last 30 minutes of cooking, mix cornstarch with cold water to create a slurry. Stir into the slow cooker liquid, replace lid, and let thicken for remaining cook time.

9. Let rest for 10 minutes after turning off heat. Garnish with fresh chopped parsley before serving.