Heat the oil in a large pan. Add the chopped onions and pepper, and sauté over a medium-low heat for 5 minutes until they start to soften.
Add the mushrooms, and cook for 5 minutes more, or until they start to release liquid. Then, add the smoked and sweet paprika, and the garlic powder.
Stir the spices through, then add the carrots, potatoes and tofu. Sprinkle over the flour, and mix well again.
Finally, add the chopped tomatoes, tomato puree, vegetable stock and fresh thyme. Stir to combine, then bring the goulash to a steady simmer.
Cover and cook for 40 minutes. After 40 minutes has passed, remove the lid, stir, and allow to cook for a further 20 minutes uncovered, or until the potatoes are soft and the vegetable goulash has thickened.
Season with salt and pepper to taste.