I wish I could claim credit for this recipe, but it came from the Kitchen Aid ice cream maker book. Please note that the processing instructions are for the KitchenAid Ice Cream Maker. As when making ice cream, your ingredients should be good and cold; I keep them refrigerated until the last minute. I make the syrup the day before so it spends overnight in the fridge.
FROZEN RECIPE HELP
 

INGREDIENTS
6 cups (1.5 L) raspberries (about 4-6 oz boxes or 2-12 oz. boxes)
1/4 cup (60 mL) plus 2 Tbs (30 mL) water
1-1/4 cups of Simple Sugar Syrup (recipe below)

INSTRUCTIONS
Combine raspberries and water in bowl of food processor fitted with metal blade. Process until very smooth; pour through a fine mesh strainer, pressing down lightly on solids to extract as much liquid as possible without forcing the solids through the strainer. Discard solids.

Pour liquid into airtight container and refrigerate at least 8 hours.

Assemble and engage freeze bowl, dasher and drive assembly as directed in the attachment instructions. Turn to STIR. Combine chilled raspberry juice and chilled simple syrup. Using a container with a spout, pour mixture into freeze bowl. Continue on STIR for 7-12 minutes or until desired consistency. Immediately transfer sorbet into airtight container and freeze for at least 2 hours before serving.

SIMPLE SYRUP
Yield: 3 cups (710 mL) syrup
INGREDIENTS
2 cups (475 mL) sugar
2 cups (475 mL) water

INSTRUCTIONS
Combine sugar and water in saucepan. Bring to boil over medium-high heat; cook and stir until sugar dissolves completely, about 10 minutes. Transfer to ice bath, stirring until well chilled. Refrigerate until ready to use.