Make Bulgogi Marinade: In a bowl, whisk together soy sauce, brown sugar, sesame oil, garlic, ginger paste, chili powder, red pepper flakes, black pepper, olive oil, and rice vinegar.
Marinate Beef: Add sliced steak and onion to the marinade. Mix well, cover, and refrigerate for at least 30 minutes (up to 24 hours).
Cook Vegetables (prepare each separately and set aside):● Mushrooms: Sauté in butter with salt and pepper until tender.● Carrots: Sauté with water, 1 tsp sesame oil, and a pinch of salt until slightly softened.● Spinach: Wilt in a covered pan with a drizzle of oil and a pinch of salt over low heat.● Cucumbers: Combine with chili paste, sugar, rice vinegar, hot water, and salt. Let sit for 10-15 minutes to quick-pickle.● Bean Sprouts: Place in a bowl, cover with boiling water, let sit for 2-3 minutes, then drain. Make Gochujang Sauce: In a small bowl, whisk together gochujang paste, soy sauce, sesame oil, sugar, water, Kewpie mayo, and rice vinegar until smooth. Adjust to taste.
Cook Bulgogi: Heat a large skillet over high heat. Add marinated beef and cook, stirring frequently, for 3-5 minutes until cooked through and caramelized.
Assemble Bowls: Place a serving of warm jasmine rice in each bowl. Arrange bulgogi and prepared vegetables in sections on top of the rice. Drizzle with gochujang sauce.
Garnish and Serve: Top each bowl with a fried egg and a sprinkle of chopped green onions. Serve immediately, instructing everyone to mix everything together thoroughly before eating.