- Combine tomato paste and stock in small bowl.
- Add vinegar, Worcestershire sauce, tamari, garlic and scallions, stirring after each addition.
- Set aside.
- Arrange tofu in single layer in non-reactive baking dish.
- Cover with marinade, and refrigerate for 1 hour, or overnight.
- Preheat oven to 400°F.
- Bake tofu in covered baking dish 30 minutes.
- Pour marinade into saucepan, and brown tofu under broiler.
- Heat marinade for 2 minutes.
- Add yeast and oregano.
- In small bowl, combine cornstarch and water, and add to marinade mixture.
- Cook sauce for 3 minutes, and serve spooned over tofu.