Preheat oven to 375°F.
Wash and rinse rhubarb and cut into ½" pieces.
Toss rhubarb with sugar, flour, and cinnamon. Place in a 2 qt baking dish.
In a separate bowl, combine topping ingredients with a fork or pastry cutter. Sprinkle over rhubarb mixture.
Bake for 35 minutes or until rhubarb is tender and topping is golden.
Cool 5-10 minutes before serving. Top with ice cream or cream.
