Cut the Spam into ½-inch thick sticks.
In a shallow dish, whisk together the eggs, flour, salt, and black pepper.
In another shallow dish, add the breadcrumbs.
Dip a stick of Spam into the egg wash, shaking off excess, then transfer to the dish of breadcrumbs. Toss the breadcrumbs all around the Spam to evenly coat it. Transfer to a baking sheet.
Option 1 Deep-fry: Heat about 1 inch of oil in a high-walled pot to 350°F. Cook 5-6 pieces of Spam at a time for 2-4 minutes until golden brown and crispy. Transfer to a wire rack to drain excess oil.
Option 2 Air-fry: Preheat your air fryer to 400°F. Place the Spam inside with a little space between each one. Spray generously with oil and air-fry for 5 minutes. Flip them over and spray generously with oil again. Air-fry for another 5 minutes.
For the katsu sauce, just combine all the ingredients in a small bowl.