Slice 450g of beef tenderloin thinly against the grain, about ⅛in / 3mm thick.
In a large bowl, mix ½ cup of grated Asian pear, ¼ cup of puréed onion, 4 minced garlic cloves, and 1 teaspoon of minced ginger.
Stir in 2 tablespoons of soy sauce, 2 tablespoons of brown sugar, 1 tablespoon of toasted sesame oil, and 1 pinch of black pepper. Add the beef and mix well. Cover and refrigerate for at least 30 minutes.
Heat a cast-iron grill pan or skillet over medium-high heat. Cook the beef, turning, until browned and cooked through.
