Mongolian Beef Noodles

Name: Mongolian Beef Noodles
Ingredients: 200 g (7 oz) beef (flank or sirloin) (cut into strips); ¼ tsp salt; 1 tsp regular soy sauce; 2 tbsp cornstarch (cornflour); ¼ tsp baking soda; 2-3 tbsp vegetable oil (for frying); 2 garlic cloves (crushed); ½ tsp ginger (minced); 3-4 Thai red chilies (chopped); ½ (~90g) green bell pepper (sliced); 1 (~60g) small carrot (cut into matchsticks); 200 g (7 oz) udon noodles; 1 green onion (green and whites separated and diced); 2 tbsp regular soy sauce; 1 ½ tsp oyster sauce; 1 tsp dark soy sauce; 2 tbsp brown sugar; ½ tsp crushed red pepper; 1 tsp toasted sesame oil; ¼ cup chicken stock; 1 tsp cornstarch (cornflour)