Start by washing the raspberries under cool running water. Slice the peaches into thin wedges and discard the pit.

In a blender, combine the raspberries and sliced peaches. Blend on high for about 30 seconds until smooth. Strain if you prefer a silkier texture.

Pour the fruit puree into a large pitcher and add the fresh lemon juice. Stir in the granulated sugar until fully dissolved.

Add cold water to the mixture and stir gently. Taste and adjust sweetness if desired.

Cover the pitcher and refrigerate for at least 30 minutes. Serve over ice and garnish with fresh mint leaves.