Heat water and sugar in a small saucepan over medium heat and whisk until sugar is dissolved, about 3 minutes. Remove pan from heat and add sliced ginger rounds. Let steep until slightly cooled, about 30 minutes.

Puree raspberries, lime juice, fresh ginger and salt in a high speed blender or food processor until smooth.

Place a fine mesh strainer over a bowl and press raspberry mixture through with a rubber spatula to separate the liquids; discard solids.

Once simple syrup has cooled, strain over same bowl and stir to combine with the raspberry liquids.

Place raspberry-ginger mixture in a bowl, cover with plastic wrap and refrigerate until cold, about 4 hours or over night.

Pour mixture into ice cream maker and freeze according to manufacturer’s instructions.