Preheat oven to 350 degrees. Clean rhubarb and cut away dry ends then chop into 1-inch pieces. Remove green tops from strawberries and cut in half. Spread rhubarb and strawberries on baking sheet and roast for 20 minutes until tender, stirring once. Remove from oven and move to refrigerator to chill.

In a food processor or blender, puree rhubarb and strawberries with sugar, water and vodka. Start the ice cream maker spinning then pour the puree in and run according to machine instructions. It should take about 20 minutes to freeze to a soft-serve consistency. Pour into a freezer-proof container and move to freezer to store.