Place 2 pounds steak of choice on cutting board. Slice steak into bite-sized pieces, making sure to cut meat against grain.
Season pieces of steak heavily on all sides with salt and freshly ground black pepper. Set steak aside.
Place large skillet on stovetop over medium-high heat. When pan is warm, add 1 tablespoon avocado oil to skillet and continue heating pan until oil is hot and shimmery.
Place steak pieces in skillet in single even layer. Sear steak 2 minutes or until browned, stirring occasionally to cook steak pieces on all sides.
Transfer browned steak to large bowl and set aside. Remove skillet from heat and let cool 1 to 2 minutes.
When skillet has cooled slightly, add prepared garlic butter to pan and return skillet to heat. Let butter melt completely.
Return steak to skillet. Cook steak 1 to 2 minutes, stirring often to coat steak in melted butter.
When steak is fully coated in melted butter, remove skillet from heat. Divide steak into desired servings. Sprinkle ½ tablespoon finely chopped fresh parsley over steak to garnish, then serve steak warm with preferred sides.