Prepare the Spicy Sauce

1. Mix the Sauce: In a small bowl, whisk together the gochujang, gochugaru (if using), soy sauce, sesame oil, sugar, and rice vinegar. Set aside.

Cook the Noodles

1. Boil the Noodles: In a pot, bring 2 cups of water to a boil. Add the ramen noodles and cook according to the package instructions (usually about 3-4 minutes). Drain the noodles and set aside, saving a little of the cooking water.

Sauté the Veggies

1. Sauté the Vegetables: While the noodles are cooking, heat the vegetable oil in a pan over medium heat. Add the onions and sauté until soft, about 2-3 minutes. Add the mushrooms and garlic and cook for another 2-3 minutes, until fragrant.

Combine Everything

1. Add the Sauce: Add the spicy sauce to the sautéed veggies and cook for another minute or two, letting the sauce thicken and become fragrant.
2. Toss the Noodles: Add the cooked noodles to the pan and toss them in the sauce, making sure each strand is well coated. If the sauce is too thick, you can add a splash of the reserved noodle cooking water to loosen it up.

Serve

1. Garnish: Serve the ramen in bowls, and top with sliced scallions, a boiled egg (if desired), and a drizzle of sesame oil for extra richness.