Japchae Sweet Potato Glass Noodles

Soak sweet potato glass noodles in warm water for 30 minutes until pliable. If not soaking, cook according to package directions. Blanch spinach in boiling water for 30 seconds, then immediately transfer to an ice bath. Squeeze out excess water and cut into 2-inch pieces. Prepare all other vegetables: julienne carrots and bell pepper, thinly slice onion and mushrooms.

If using beef, combine sliced beef with 1 tbsp soy sauce, 1 tsp sugar, 1 tsp minced garlic, and a pinch of black pepper. Mix well and let marinate for at least 15 minutes.

Heat 1/2 tbsp vegetable oil in a large pan or wok. Sauté carrots for 2-3 minutes until slightly tender. Remove and set aside. Repeat with onions, mushrooms, and bell peppers, cooking each separately until tender-crisp, adding a pinch of salt to each if desired. Sauté spinach briefly with 1 tsp sesame oil and a pinch of salt. Remove and set aside all vegetables.

In the same pan, cook the marinated beef until browned and cooked through. Remove and set aside. If cooking noodles from dry, boil them according to package instructions until tender and chewy (usually 6-8 minutes), then drain and rinse with cold water. Cut the cooked noodles into shorter, manageable lengths (about 6-8 inches) with kitchen shears.

In a large bowl, combine the remaining 4 tbsp soy sauce, 3 tbsp sesame oil, 1 tbsp sugar, 2 tsp minced garlic, and 1/2 tsp black pepper. Whisk until well combined.

Add the cooked noodles, all sautéed vegetables, and cooked beef (if using) into the large bowl with the dressing. Using clean hands or tongs, gently toss everything together until all ingredients are evenly coated with the sauce.

Return the mixture to the pan and stir-fry over medium heat for 2-3 minutes, ensuring everything is heated through and the flavors meld. Taste and adjust seasoning if necessary. Garnish with toasted sesame seeds and serve warm or at room temperature.