Preheat oven to 400°F and line a baking sheet with foil, then spray with cooking spray.
Mix cream cheese, diced jalapeños, and shredded cheddar together in a bowl and refrigerate for 10 minutes.
Combine ground beef, breadcrumbs, egg, garlic powder, and salt in a large bowl.
Flatten each portion of meat, place a small ball of cream cheese filling in the center, and seal the meat completely around it.
Roll each meatball in panko breadcrumbs, pressing gently to adhere.
Place on the prepared sheet, spray the tops lightly with cooking spray, and bake for 22-25 minutes until golden and cooked through.