Dice 1 pound beef sirloin steak or tenderloin into bite-sized pieces, trimming off any excess fat or sinew. Place the steak bites in a gallon-sized resealable plastic bag or a shallow bowl.
Add in 2 tablespoons lemon juice, 1 tablespoon olive oil, 1 tablespoon Worcestershire sauce, 1 tablespoon apple cider vinegar, 1 teaspoon onion powder, 1 teaspoon garlic powder, 1 teaspoon salt and 1/2 teaspoon black pepper to the steak. Toss to coat the steak evenly. Seal the bag or cover the bowl, and refrigerate for 1 to 8 hours to marinate.
When ready to cook, Preheat the air fryer to 400°F (200°C).
Cut 1 pound red baby potatoes into bite-sized pieces and add them to a medium mixing bowl. Toss with 1 tablespoon olive oil and 1 teaspoon salt until evenly coated.
Add the potatoes to the air fryer basket in an even layer. Cook for 10 minutes, tossing the potatoes halfway through the cooking cycle.
After the potatoes have cooked and are near fork-tender, add the marinated steak bites to the air fryer basket with the potatoes. Cook for an additional 4 to 8 minutes, tossing halfway through.
Serve hot. Sprinkle with 1/4 cup freshly grated parmesan cheese before serving.
Notes
Medium-Rare (135°F): Check your steak bites toward the 4-5 minute mark during cooking.
Medium (145°F): Keep an eye on your steak bites around 5-6 minutes.
Medium-Well (150°F): Cook for about 6-7 minutes, but start checking earlier to avoid overcooking.
Well Done (160°F): If you like your steak well done, aim for 7-8 minutes, checking frequently to prevent dryness.