Begin by pressing the tofu to remove excess moisture, then cut it into 1-inch cubes.

Heat a pan over medium heat with a splash of neutral oil and pan-fry the tofu for 10-15 minutes until golden and crisp.

In a medium bowl, whisk together gochujang, tomato ketchup, water, sesame oil, sugar, rice vinegar, and soy sauce to create the sauce.

In a large pan or wok, heat more oil over medium-high heat and stir-fry white onion and white parts of green onions for 3-4 minutes.

Add minced garlic and stir for an additional 30 seconds until fragrant.

Incorporate mushrooms and cook for 5 minutes until slightly browned.

Combine the cooked tofu with the vegetables, pour over the sauce, and simmer for 1-2 minutes.

Plate the stir-fry, garnish with green onion parts and sesame seeds, and serve hot with steamed rice.