Dice the steak into 1-inch pieces and place into a zip top bag.
Whisk together the hot water and salt until the salt is nearly dissolved. Add the remaining ingredients and whisk well.
Pour the marinade over the steak. Seal the bag and marinate for 1 to 8 hours.
When ready to cook, drain the marinade from the steak and pat the steak bites dry.
Add steak bites to the basket of your air fryer in a single layer. You may need to work in batches.
Air fry at 400 degrees for 10 minutes, shaking the basket halfway through cooking. This will result in a medium doneness, depending on the thickness of your steak. Continue cooking for longer if you prefer your steak more well done.
To make the garlic butter, melt the butter in a small bowl and whisk in the minced garlic, garlic salt, and parsley.
Drizzle the butter over the steak bites, toss well, and let rest for 5 minutes before serving.
Notes
Cut steak into evenly sized pieces to ensure the same doneness throughout. Cook for more or less time to reach your desired level of doneness.Do not marinate longer than 8 hours or the steak will start to get too salty. Since the steaks are smaller, they soak up the flavor quicker.