In a saucepan combine rhubarb, water and maple syrup. Over med-high heat, bring to a boil, then lower heat and simmer until rhubarb is very tender. Add raspberries and stir until well combined. Remove from heat and set aside to cool completely.
Using a chilled bowl and beaters, whip cream until soft peaks form. Add yogurt and continue to beat until stiff peaks form. Do not overbeat.
Alternate layers of raspberry-rhubarb compote in dessert glasses and top with an extra dollop of whipped cream. Garnish with fresh mint leaves or with cookie crumbs. Keep chilled until serving time.
This dessert is best served on the day it's made, but you can make the rhubarb-raspberry mixture ahead of time and refrigerate it.