Part-freeze steak to make it easier to cut each piece into very thin slices. Place steak on a plate and spread with garlic, 1 tablespoon oil and capsicum. Cover and refrigerate for 45 minutes.
Pour 2½ tablespoons oil into a heavy-based pan, ensuring the base is coated. Separate the noodles with your hands. Heat oil to medium, add noodles and press them down with a spatula. Heat until base is golden and crisp. Don't lift the noodle pancake for about 15 minutes as it will break up.
Loosen edges and base of pancake gently. Place large plate over the pan and quickly invert the pan to settle the pancake on the plate. Gently slide the pancake back into the pan, uncooked side down, and continue cooking for 5-10 minutes. Return pancake to plate in the same manner and keep warm in very slow oven.
In same pan, heat over high heat 2½ tablespoons oil. Add meat and capsicum mixture and sear quickly on both sides. Don't overcook. Mix sugar, fish sauce, stock and conflour until smooth and add to steak. Turn meat to absorb flavours, then remove. Stir sauce rapidly until thick, returning steak briefly to coat with sauce.
