Flank Steak With East Asian Marinade (Crowd Cow)

Ingredients

• 1 1-lb flank steak, trimmed of fat
• 1/4 cup rice wine
• 3/4 cup pineapple juice
• 1/2 cup soy sauce
• 1 tbsp red wine vinegar
• 6 green onions, thinly sliced
• 2 lemongrass stalks, white part only, sliced thickly
• 4 garlic cloves, minced
• 1 tbsp tomato paste
• 2 tsp Dijon mustard
• 1 quart Beef stock, unsalted
• Salt and pepper, to taste