In a medium saucepan, combine rhubarb with rose petals, if using, and ¼ cup maple syrup. Bring to a boil over medium heat, reduce to a simmer and cook for 10 minutes, until rhubarb is soft. Let cool to room temperature and chill in the refrigerator for about an hour.
Combine well-chilled yogurt with half of the rose-rhubarb mixture, remaining ¼ cup of the maple syrup and rose water.
Process in an ice cream maker for 20 minutes or according to the manufacturer's instructions. Spoon into a container, alternating between layers of frozen yogurt and the remaining rose-rhubarb mixture. Eat right away as soft serve or place in the freezer and make sure to remove from the freezer 10-15 minutes before serving.
Notes
If you don't have an ice cream maker, you can make popsicles. Just pour the final rhubarb-yogurt mixture into popsicle molds and freeze. Rose petals are optional, rose water gives plenty of flavor.
Recipe by Golubka Kitchen at https://golubkakitchen.com/rose-and-rhubarb-frozen-yogurt/