Place onion half in a small microwavable bowl with a small amount of water, about 2 tablespoons. Cover the bowl with a plate set upside down over the bowl, and microwave 2-3 minutes until the onion is softened.
In a stew pot, heat oil over medium-high heat. While oil heats, chop softened onion. Add chopped onion to stew pot, and cook about 7 minutes or until onion starts to brown. Add soy crumbles to pot, and continue to cook about 3 minutes more. Add tomato sauce or paste, crushed tomatoes, and broth, and cook an additional 3 minutes, scraping any browned bits off the bottom of the pan.
Add remaining ingredients except fresh oregano to the pot, bring to a boil, reduce heat to low, and simmer 8 minutes. Taste for salt and pepper before serving. Garnish with fresh oregano if desired.