Prepare the tomatoes: If using Roma tomatoes, slice them in half lengthwise. If using cherry tomatoes, simply wash them well. Place the prepared tomatoes in a medium, non-reactive bowl.

Prepare the marinade: In a small bowl, whisk together the olive oil, red wine vinegar, minced garlic, dried oregano, salt, and black pepper until well combined.

Combine ingredients: Pour the marinade evenly over the tomatoes in the bowl.

Marinate: Gently toss the tomatoes to ensure they are fully coated with the marinade. Cover the bowl with plastic wrap and refrigerate for at least 30 minutes, or up to 4 hours, allowing the flavors to meld.

Serve: Just before serving, remove the bowl from the refrigerator. Stir in the fresh basil chiffonade.

Enjoy the marinated tomatoes chilled or at room temperature, perhaps served with crusty bread for dipping in the residual juices.