Or use unflavored yoghurt for a frozen yoghurt. The trick is the beating to break up the ice crystals. Make sure that no icy patches are left on the edges when you do the beating. What you want to do is get it closer and closer to freezing solid without ice crystal formation. It helps to set your freezer temperature a little colder than you would usually keep it during the process.
Or use unflavored yoghurt for a frozen yoghurt. The trick is the beating to break up the ice crystals. Make sure that no icy patches are left on the edges when you do the beating. What you want to do is get it closer and closer to freezing solid without ice crystal formation. It helps to set your freezer temperature a little colder than you would usually keep it during the process.