Cost per Serving:
1. Preheat oven to 400°F. Mash tomatoes until chunky. Warm oil in an ovenproof skillet over medium heat. Sauté onion for 7 minutes until tender. Add garlic; sauté 1 minute. Season with salt and pepper.
2. Add tomatoes; simmer, stirring, until most of liquid has evaporated, about 5 minutes. Stir in shrimp and oregano, then sprinkle feta on top.
3. Place skillet in oven; bake until shrimp are opaque, approximately 10 minutes. Serve hot.