Sauté onion in hot oil in a Dutch oven over medium-high heat 4 to 5 minutes or until tender. Add garlic, and cook 1 minute. Stir in tomatoes and next 8 ingredients. Bring to a boil; reduce heat to low, and simmer, stirring occasionally, 15 minutes. Stir in spinach and chopped parsley; cook 5 minutes. Top with crumbled feta cheese, if desired.