1: First thing you do is to go ahead and preheat your oven to 350 degrees F.
2: Next grease one of your 9x13 inch baking pans.
3: Then take a large bowl and combine sugar, tapioca, cornstarch and salt.
4: Place rhubarb that you have cut up and the raspberries into a bowl and coat them with dry ingredients.
5: Pour these ingredients into your baking pan.
6: In another bowl you will mix together the brown sugar, canna-flour and oats.
7: Then add in the canna-butter and mix until the mixture resembles pea-sized crumbs.
8: Go ahead and spread this on top of fruit mixture.
9: Bake in your preheated oven for at least 45 minutes or until the rhubarb is tender.