Dice 3 cups fresh rhubarb and place into a well-greased 9X9 baking dish. Sprinkle with 1 tsp. flour, 1/2 tsp cinnamon, and 1/8 tsp. salt.
In a bowl, combine 1/2 cup of rolled oats (old-fashioned or instant), 1/2 cup brown sugar, 1/4 cup flour, 1/8 tsp. baking powder, and 1-4 cup soft margarine such as Becel. Rub these ingredients together. This makes a crumbly crust mixture. Sprinkle over the rhubarb evenly.
Bake at 350F in the oven until the rhubarb is tender, about 30-40 minutes.
This tastes wonderful with just a dollop of vanilla ice cream!