1. In a large saucepan, combine the raspberries, honey, vanilla, water, and salt. Place over medium heat and cook, stirring gently until the honey is dissolved and the berries have softened and given off some of their juices, 5 to 8 minutes. Remove the pan from the heat and allow to cool.
2. Transfer to a bowl and mix in the coconut, yogurt, buttermilk, and lime juice. Cover and place the bowl in the refrigerator for a few hours to chill thoroughly.
3. Freeze the mixture in an ice cream maker according to the manufacturer’s instructions. You can eat the frozen yogurt right away for a softer version, or freeze it for about 2 hours for a firmer consistency.