Preheat a large sauté pan over medium heat. If using oil, add it to the pan with the onion, celery and bell pepper. If not using oil, add a splash of water as needed to prevent sticking. Cook for 5 to 7 minutes, stirring occasionally. When the onions are translucent, add the garlic, stir, and cook for another 2 minutes.
Crumble the tofu into the pan. Sprinkle the tofu with the nutritional yeast, salt, cayenne, paprika, thyme, oregano, and red pepper flakes. Stir to combine. Cook for several minutes or until the tofu is hot. Add a splash of water as needed to prevent sticking.
Add the chopped greens to the pan, stir to combine, reduce heat to medium-low, cover and cook 3 to 5 minutes or until the greens are softened. Taste and add more salt and pepper if desired.
Serve with fresh tomato.
Store leftover tofu scramble in the refrigerator for up to 4 days.