First, drain the tofu and press it carefully to remove excess moisture. Slice it into thin, steak-like pieces. In a bowl, combine the flaky sea salt, dark soy sauce, dark brown sugar, Marmite, mustard powder, nutritional yeast, Worcestershire sauce, minced garlic, black pepper, and liquid smoke. Add the tofu to this marinade and let it soak in the flavors for at least 30 minutes. You can even do this a day ahead for more flavor.

In a large skillet, heat 2 tablespoons of vegetable oil over medium heat. Once it's hot, add the marinated tofu slices. Cook them until they are golden brown and slightly crispy, about 4-5 minutes per side. When done, remove the tofu and set it aside. Don’t clean the skillet just yet; the leftover flavors will add depth to the veggies.

In the same skillet, add a drizzle more oil if necessary. Throw in the chopped onion, bell pepper, and mushrooms. Sprinkle with the sugar, flaky sea salt, black pepper, and dried thyme. Sauté them until they soften, about 8-10 minutes. Stir in the minced garlic just for the last minute to avoid burning it.

In a medium saucepan over low heat, whisk together the soy milk, tapioca starch, nutritional yeast, onion salt, garlic powder, paprika, turmeric, and water. Stir continuously to avoid lumps until it thickens up. Now, toss in the vegan cheese, butter, white vinegar, miso paste, and Dijon mustard. Mix until everything is well combined and gooey. If it’s too thick, you can add a splash more plant milk.

Spread the softened vegan butter over the insides of each hoagie roll. Sprinkle the dried oregano on top for an extra kick of flavor. Now, layer the tofu and the sautéed veggies generously into each roll. Drizzle with the creamy cheese sauce, and don’t hold back—you want it gooey!

To add some extra texture and warmth, preheat the oven to 180°C (350°F). Place the assembled sandwiches on a baking tray and toast them in the oven for about 10 minutes until the rolls are slightly crispy.