Heat grill on medium-high (approximately 400F). While grill preheats, prep foil packs. Using heavy duty foil, tear 4 sheets of foil and spray with nonstick cooking spray.
Using a chef’s knife, quarter potatoes, dice onion, and slice peppers. Cube sirloin into approx 2-inch chunks. Combine steak and chopped veggies in a medium bowl, with olive oil, minced garlic, paprika, salt and pepper.
Divide the mixture evenly into each the prepared sheet of foil: four total, and make a pack, wrapping the mixture in each foil pack.
Grill foil packs for 25-30 minutes, until veggies are tender. Remove from heat and top with fresh parsley and crushed red pepper, if desired. Serve immediately and enjoy!