In a small bowl, combine the melted butter and minced garlic. Stir well to mix.
Place the cubed sirloin steak into the crockpot.
Sprinkle the salt, black pepper, smoked paprika, and onion powder evenly over the steak bites.
Pour the garlic butter mixture over the seasoned steak bites, stirring gently to coat all pieces.
Cover the crockpot and cook on low heat for 3 to 3.5 hours, or until the steak bites are tender and cooked to your desired doneness.
Once cooked, sprinkle the chopped fresh parsley over the steak bites and gently stir to combine.
Serve the steak bites warm, spooning any garlic butter sauce from the crockpot over the top.