Bibim Naengmyeon (Korean Spicy Cold Noodles)

Name: Bibim Naengmyeon (Korean Spicy Cold Noodles)
Prep time: 10 min
Cook time: 5 min
Total time: 15 min
Cuisine: Korean
Ingredients: 1/2 cucumber ((about 120g)); 4 oz Korean radish ((or daikon) (optional)); 3.5 oz thinly sliced beef for hot pot; 1/4 Korean pear ((or Asian/Nashi pear, red apple) (to garnish)); 2 servings naengmyeon noodles ((about 150g for each serving) (or somyeon noodles)); 1-2 hard-boiled eggs ((to serve)); Generous pinch of toasted sesame seeds ((to garnish)); 1 cup white vinegar; 4 tbsp sugar; 1 tsp salt; 1 tsp hot mustard ((optional)); 4 cups water; 1 tbsp Korean beef stock powder (dasida); 1 tsp sugar; 1 tsp soy sauce; 5 oz Korean pear ((or Asian/Nashi pear, red apple)); 2.5 oz yellow onion; 1 oz green onions; 2 cloves garlic; 2 tbsp water; 3 tbsp Korean chili paste (gochujang); 3 tbsp sugar; 4 tbsp soy sauce; 3 tbsp Korean chili pepper powder/flakes (gochugaru); 3 tbsp white vinegar; 1/2 tbsp Korean beef stock powder (dasida); 3 tbsp toasted sesame oil