Whisk the yogurt with the sugar, salt, vanilla and honey or agave nectar in a bowl. Cover and place in the fridge while preparing the fruits.

In a food processor or blender, puree the mango and raspberries (together or separately). Strain to separate the seeds and fiber from the fruits. The puree should amount to at least 1 1/2 cups (up to 2 cups). Stir in the honey and lemon juice. Adjust to taste.

Mix with the yogurt mixture in the fridge. Pour the mixture into the ice cream maker and process according to the manufacturer's instructions. You can enjoy your frozen yogurt right away. But should you want to freeze it longer, just let the yogurt soften a little before serving.

To make this without an ice cream maker, just place the yogurt mixture in a freezer-safe container. Cover and freeze immediately. After 30-40 minutes take out of the freezer then whisk to break up the ice crystals. Freeze again for another 40 minutes. Repeat the process one more time and then freeze finally for another 1-2 hours or until firm to your liking. Serve thereafter. :-) Enjoy!