1. In a small saucepan over high heat, bring water, sweetener, and 15 mint leaves to a boil. Turn off heat and allow to steep for 10 minutes. 2. Strain liquid into a blender and add lime juice, rum, and ¼ cup raspberries. Process until smooth. 3. Strain mixture into a measuring cup with a spout. Finely chop 5 mint leaves and stir into mixture. 4. To each popsicle mold, add 6 raspberries. Then fill ¾ of the way with mojito mixture. Add popsicle sticks and freeze until completely set, at least 4 hours.