This recipe is a fun, refreshing way to use summer-ripe tomatoes and fresh herbs. It's wonderful as a starter or as a between-course palate cleanser.
Combine all the ingredients except the basil in a large pan, cover, and cook on high heat until the tomatoes are very soft and the liquid thickens. Remove from heat and transfer to a blender or food processor. Purée until smooth, then strain through a fine mesh sieve. Chill the mixture until cold.
Place the tomato mixture in an ice cream maker. Add the basil, turn on the machine, and process according to manufacturer's instructions. Freeze for at least 2 hours before serving.