In a medium bowl, combine salt, black pepper, smoked paprika, and dried thyme.
Toss the sirloin steak cubes in the seasoning mixture until evenly coated.
In a skillet over medium-high heat, melt 2 tablespoons of butter.
Add the seasoned steak bites to the skillet and sear for 2 minutes on each side until browned but not fully cooked.
Transfer the seared steak bites to the crockpot.
In the same skillet, add the remaining 2 tablespoons of butter and minced garlic. Cook for 1-2 minutes until fragrant, stirring frequently to prevent burning.
Add Worcestershire sauce and beef broth to the skillet, stirring to combine and scraping up any browned bits from the pan.
Pour the garlic butter sauce over the steak bites in the crockpot.
Cover and cook on low for 3 to 3.5 hours until steak bites are tender.
Before serving, sprinkle chopped fresh parsley over the steak bites and stir gently to combine.
Serve warm with your favorite sides.