Place the tofu in a bowl with the flour, half the thyme, paprika, cayenne, salt, ground black pepper, 1 tsp Cajun seasoning and flour. Toss to mix.
Heat 1 tbsp of oil in a large nonstick skillet or wide nonstick saucepan. Shake the excess flour off the tofu (reserve the excess flour) and place the tofu in the pan in a single layer. Fry on all sides until golden-brown. Remove to a dish.
Heat the remaining oil in the same pan and add the flour remaining from coating the tofu. Cook for a few minutes, stirring constantly, until the flour turns a deeper color that resembles the color of peanut butter. Don't leave the flour unattended or let it burn. This should take no more than 5-7 minutes on medium-low heat.
Add celery, onions and bell peppers along with the garlic and remaining thyme and a dash of salt and ground black pepper. Saute for about three to four minutes or until the vegetables become soft but are not fully cooked. If the flour sticks to the bottom, scrape it up with a spatula.
Add the mushrooms and continue cooking a couple more minutes. Then add the tomato paste, worcestershire sauce, soy sauce, hot sauce and remaining 1 tsp of Cajun seasoning along with 2 cups of vegetable stock or water. Mix well and bring to a boil. Lower the heat to a simmer and let the sauce cook five more minutes.
Stir in the tofu, scallions and parsley. Turn off heat.