Heat olive oil in a large skillet over medium-high heat. Season filet bites evenly with salt and pepper.
Sear steak bites in batches for 1–2 minutes per side, just until browned. Do not cook through.
In the same skillet, melt butter. Add garlic and sauté for 30–45 seconds, until fragrant.
Transfer seared filet bites to the crock pot. Pour garlic butter evenly over the steak.
Cover and cook on HIGH for 45 minutes, gently stirring once halfway through.
Spoon garlic butter over the filet bites and garnish with fresh parsley before serving, if desired.