|Time||15 minutes, plus 1 hour baking|
- 1 cup brown sugar
- 3/4 cup oats
- 1 cup flour
- 1/2 cup butter
- 1 tsp cinnamon
- 4 cup uncooked cut up rhubarb
- 1 cup white sugar
- 2 tbsp corn starch/cornflour
- 1 cup water
- 1 tsp. vanilla
- Mix brown sugar, oats, flour, butter and cinnamon until crumbly.
- Press 1/2 of mixture into a 9 inch square pan.
- Cover crumb mixture with cut up rhubarb.
- Mix white sugar, cornstarch and water. Cook until clear and thick, stirring constantly. Add vanilla and stir.
- Pour over rhubarb. Sprinkle with remaining crumb mixture over the top.
- Bake for 1 hour at 180°C.
Alternative method 
Many cooks use cold butter and rub the fat into the dry ingredients. It is also common not to have a crumble layer on the bottom, just on top of the rhubarb. Finally the cornstarch sauce is frequently omitted. Raw rhubarb and sugar alone are used. The rhubarb juice acts as a sufficient sauce.