Preheat the air fryer to 400°F. While it's preheating, melt the butter, then add all cowboy butter ingredients in a small bowl and mix well. Take the steak out of the fridge to let come to room temperature.
1 stick Salted butter, 1 Tbsp. Lemon zest, 1 Tbsp. Lemon juice, ½ tsp. Garlic powder, ¼ tsp. Red pepper flakes, ½ tsp. Sea salt, ½ tsp. Black pepper, ½ Tbsp. Dijon mustard, ½ tsp. Worcestershire sauce
Pat the steak dry with paper towels, and cut it into 1-inch cubes. Add the steak cubes to a large bowl, then add in 3 Tablespoons of cowboy butter and toss well. Reserve the rest of the cowboy butter, and don't cross-contaminate!
1 lb Sirloin steak, Cowboy Butter sauce
Lay a layer of aluminum foil down at the bottom of the air fryer basket or tray, and wipe with oil. Don't spray it; spray oil damages nonstick! Then spread out the steak bites so none are touching. If they don't all fit, cook them in batches.
1 Tablespoon Olive oil
Air fry your steak bites at 400°F for 10-15 minutes, depending on desired level of doneness. I like nicely pink medium-rare steak, so I cooked mine for 10 minutes!
While the steak is cooking, pour the cowboy butter into a small saucepan over medium heat and bring to a boil. Reduce the heat and let simmer until the steak is done, about 15 minutes.
Sprinkle the steak bites with parsley, then serve with cowboy butter for dipping and enjoy!
1 Tbsp. Parsley