1. In the bowl of a food processor, combine tomatoes and rosemary, and pulse until finely chopped but not completely puree. Add oil, and pulse until combined, about 5 seconds.

2. Transfer mixture to an airtight container. Refrigerate at least 2 days to let flavors develop. At this point, oil can be stored up to 10 days in the refrigerator. To store longer than 10 days, strain mixture through a double layer of moistened cheesecloth into another airtight container, discarding solids. Before serving, bring to room temperature.