Place raspberries in a food processor and pulse until well pureed. Pour the raspberry puree through a fine mesh strainer into a bowl; set aside.
Pour 1 cup of water into a medium-size saucepan over medium-high heat, then stir in the sugar. Continue cooking over heat until sugar is dissolved and liquid turns from cloudy to clear again.
Remove from the stovetop pour into a large pitcher or jug. Allow to cool for 15 minutes before stirring in the puree, remaining water and lemon juice, stir to combine. Refrigerate for at least 30 minutes before serving. Serve with fresh raspberries, lemon slices, mint and ice.
Notes
*You can swap out the 4 cups of water for a liter of sparkling water. Remove the mixture from the stovetop, allow to cool, then add in the raspberry puree and lemon juice. Add COLD sparkling water right before serving, mix to combine.