My own recipe is similar, only hotter and authentically New Mexican ;)

Roast half the tomatoes, the garlic and the jalapeños on a cookie sheet for approximately 15 minutes at 450 F. (until all are browned/lightly blackened.
Chop all remaining ingredients finely or use a food processor, particularly the garlic.
Add olive oil, mix well. Chill for at least 2 hours before serving.